Life Processes Topic Wise Assertion Reason Questions

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Assertion (A): Gaseous exchange for photosynthesis primarily occurs through stomata on leaves.

Reason (R): Stomata are tiny pores present on the surface of the leaves, facilitating massive amounts of gaseous exchange.

Assertion (A): The opening and closing of stomatal pores are regulated by guard cells.

Reason (R): Guard cells swell when water flows into them, causing the stomatal pore to open.

Assertion (A): Plants obtain water for photosynthesis from the soil through their roots.

Reason (R): Water is reduced to carbohydrates during photosynthesis.

Assertion (A): Nitrogen is an essential element for plants.

Reason (R): Nitrogen is used in the synthesis of proteins and other compounds in the plant body.

Assertion (A): Plants can only take up nitrogen in the form of inorganic nitrates or nitrites.

Reason (R): Bacteria in the soil convert atmospheric nitrogen into organic compounds that plants can absorb.

Assertion (A): Heterotrophs use bio-catalysts called enzymes to break down complex substances.

Reason (R): Enzymes are necessary to convert simple food materials into complex ones for body upkeep.

Assertion (A): The green dots observed in a cross-section of a leaf under a microscope are stomata.

Reason (R): These green dots are cell organelles called chloroplasts which contain chlorophyll.

Assertion (A): Photosynthesis involves the reduction of carbon dioxide to carbohydrates.

Reason (R): Carbohydrates are complex substances that need to be broken down before being used for energy by the plant.

Assertion (A): The internal energy reserve in plants is stored in the form of glycogen.

Reason (R): A somewhat similar situation is seen in humans where some energy from food is stored as glycogen.

Assertion (A): Massive amounts of gaseous exchange occur in leaves through stomata for the purpose of photosynthesis.

Reason (R): Plants close these pores when they do not need carbon dioxide for photosynthesis to prevent large amounts of water loss.

Assertion (A): Energy is needed to maintain a state of order in our body.

Reason (R): This is why we use up energy when we walk or ride a bicycle.

Assertion (A): The steps of photosynthesis, such as light absorption and carbon dioxide reduction, must occur one immediately after the other.

Reason (R): Desert plants demonstrate this by taking up carbon dioxide at night and processing it during the day.

Assertion (A): Nitrogen, phosphorus, iron, and magnesium are obtained from the soil by terrestrial plants.

Reason (R): These are essential raw materials for building the plant’s body.

Assertion (A): The process of photosynthesis allows autotrophs to convert stored forms of energy into substances from the outside.

Reason (R): Autotrophs take in carbon dioxide and water to convert them into carbohydrates.

Assertion (A): Stomata are the only pores for gaseous exchange in plants.

Reason (R): Massive amounts of gaseous exchange occur through stomata for photosynthesis.

Assertion (A): Organisms require bio-catalysts called enzymes to break down complex substances into simpler ones.

Reason (R): Enzymes are essential for autotrophs to convert inorganic sources into food material.

Assertion (A): Chloroplasts are small green dots found within cells of a leaf.

Reason (R): They contain chlorophyll, which is the green pigment responsible for absorbing light energy.

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Analogy for Conceptual Understanding: Think of a plant as a solar-powered factory. The chloroplasts are the main assembly lines within the factory cells, and chlorophyll is the specific solar panel on those lines, specialized in capturing sunlight.

The stomata are like the factory’s loading docks, opening and closing to let in raw materials (carbon dioxide) and release waste (oxygen), but they must also be managed carefully to prevent too much valuable water from escaping. The roots are the supply lines for water and other essential minerals from the ground.

All these components work together to take simple, inorganic raw materials and transform them into energy-rich carbohydrates, which are the factory’s product, fueling its operations and growth, much like a well-run factory efficiently converts raw goods into valuable products for consumption or storage.

How do organisms obtain nutrition 

Instructions: In each of the following questions, a statement of Assertion (A) is given followed by a corresponding statement of Reason (R).

Choose the correct option from the following:

(A) Both A and R are true and R is the correct explanation of A.

(B) Both A and R are true but R is not the correct explanation of A.

(C) A is true but R is false.

(D) A is false but R is true.

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Assertion (A): The design of an organism’s digestive system is largely determined by the type of food it consumes and its method of obtaining that food.

Reason (R): Different nutritional strategies necessitate varied anatomical and physiological adaptations for processing nutrients.

Assertion (A): In single-celled organisms, food intake can occur across the entire cell surface.

Reason (R): As the complexity of an organism increases, different parts become specialized to perform distinct functions, including food acquisition.

Assertion (A): Amoeba engulfs food particles using temporary finger-like extensions of its cell surface.

Reason (R): These temporary extensions, called pseudopodia, are permanent structures of the cell membrane.

Assertion (A): Digestion in Paramoecium occurs globally across its entire cell surface.

Reason (R): Paramoecium is a unicellular organism that possesses a definite shape and takes in food at a specific spot.

5. Question: Assertion (A): Simpler substances, resulting from the breakdown of complex food within the food-vacuole of Amoeba, become available for cellular use.

Reason (R): These simpler substances diffuse into the cytoplasm from the food-vacuole.

6. Question:

Assertion (A): The specific feeding mechanism of an organism, such as the use of pseudopodia in Amoeba or cilia in Paramoecium, is determined by its overall cellular structure.

Reason (R): Amoeba has a flexible cell surface allowing for temporary extensions, while Paramoecium has a definite shape requiring specific food collection tools.

7. Question:

Assertion (A): Cilia play a crucial role in the nutritional process of Paramecium.

Reason (R): Cilia cover the entire surface of the Paramecium cell and their movement directs food particles towards a specific ingestion spot.

8. Question:

Assertion (A): Complex organisms are characterized by the absence of specialized parts for different functions.

Reason (R): As the complexity of an organism increases, different parts become specialized to perform different functions.

9. Question:

Assertion (A): The formation of a food-vacuole is a critical step in the intracellular digestion process of Amoeba.

Reason (R): The food-vacuole provides a confined environment where complex food substances can be broken down into simpler, absorbable forms.

Answer: (A)

Explanation: Both the assertion and the reason are true, and the reason correctly explains the importance of the food-vacuole. The source describes its formation by the fusion of extensions over food particles and explicitly states that “Inside the food-vacuole, complex substances are broken down into simpler ones”, making it essential for digestion.

10. Question:

Assertion (A): Undigested material in Amoeba is permanently stored within the cell to prevent nutrient loss.

Reason (R): The remaining undigested material is moved to the surface of the cell and thrown out.

Answer: (D)

Explanation: The assertion is false. Undigested material is not permanently stored; it is expelled. The reason is true, accurately describing the egestion process in Amoeba: “The remaining undigested material is moved to the surface of the cell and thrown out”.

11. Question:

Assertion (A): Ingestion of food in Paramoecium is facilitated by the movement of cilia.

Reason (R): The cilia in Paramoecium directly digest the food substances before they enter the cell.

Answer: (C)

Explanation: The assertion is true; cilia are responsible for moving food to a specific spot for intake in Paramoecium. However, the reason is false. Cilia are involved in movement of food, not its direct digestion. Digestion of complex substances occurs inside the food-vacuole (implied by the general description of unicellular digestion and specific mention for Amoeba).

12. Question:

Assertion (A): The structure of the digestive system in various organisms shows considerable diversity.

Reason (R): This diversity reflects the differing food sources available in various habitats.

Answer: (B)

Explanation: Both the assertion and the reason are true, but the reason is not the correct explanation of the assertion. The assertion is true, as indicated by the variations between Amoeba and Paramoecium, and the general statement about differing digestive systems. The reason is also true in a biological context, as food source influences adaptation. However, the source states that the digestive system differs because “the food and the way it is obtained differ”, implying both food type and acquisition method are the reasons for difference, not just the food source (habitat). The reason doesn’t fully capture the source’s explanation.

Assertion (A): The process of nutrition in Amoeba involves sequential steps: ingestion, digestion, absorption, and egestion.

Reason (R): After the breakdown of complex substances in the food-vacuole, simpler substances diffuse into the cytoplasm, and any remaining undigested material is expelled.

Answer: (A)

Explanation: Both the assertion and the reason are true, and the reason correctly explains the sequence of events in Amoeba’s nutrition. The source describes food being taken in, complex substances broken down inside the food-vacuole, simpler ones diffusing into the cytoplasm, and undigested material being thrown out, which corresponds to ingestion, digestion, absorption, and egestion.

Assertion (A): The definitive shape of Paramoecium allows it to consume food from any point on its cell surface.

Reason (R): Paramoecium’s definite shape necessitates food intake at a specific spot.

Answer: (D)

Explanation: The assertion is false. A definite shape, as seen in Paramoecium, restricts food intake to a specific spot, rather than allowing it from anywhere on the surface. The reason is true, directly stating that Paramoecium “has a definite shape and food is taken in at a specific spot”.

Assertion (A): Paramoecium’s cell surface is entirely covered by cilia.

Reason (R): These cilia are primarily used for anchoring the Paramoecium to a substrate.

Answer: (C)

Explanation: The assertion is true; the source states that cilia “cover the entire surface of the cell”. However, the reason is false. The source specifies that cilia’s function is to move food to a specific spot, not for anchoring.

Assertion (A): The internal breakdown of complex food substances in unicellular organisms primarily occurs in specialized digestive organelles located in the cytoplasm.

Reason (R): In Amoeba, complex substances are broken down into simpler ones inside the food-vacuole.

Answer: (B)

Explanation: Both the assertion and the reason are true, but the reason is not the correct explanation of the assertion. The assertion is broadly true for Amoeba, where the food-vacuole acts as a specialized organelle. The reason specifies this breakdown in Amoeba’s food-vacuole. However, the reason describes where the breakdown occurs, not why it happens in specialized organelles in unicellular organisms in general. The assertion is a broader statement, and the reason is a specific example.

Assertion (A): The evolution of functional specialization is a direct consequence of increasing organismal complexity.

Reason (R): In simpler organisms, the entire body surface often handles multiple functions, which becomes inefficient with increasing size and complexity, necessitating dedicated structures.

Answer: (A)

Explanation: Both the assertion and the reason are true, and the reason correctly explains the assertion. The source states, “But as the complexity of the organism increases, different parts become specialised to perform different functions”. The reason elaborates on the conceptual basis for this specialization, highlighting the limitations of relying on the entire surface for complex needs.

Assertion (A): In Paramoecium, undigested material is expelled through temporary finger-like extensions similar to Amoeba.

Reason (R): In Amoeba, the remaining undigested material is moved to the surface of the cell and thrown out.

Answer: (D)

Explanation: The assertion is false. The source describes Amoeba using temporary extensions for food intake, not Paramoecium for egestion, nor does it describe Paramoecium’s egestion method in detail, only its food intake. The reason is true, accurately describing the egestion process in Amoeba.

Assertion (A): The mechanisms of food acquisition in single-celled organisms can vary significantly.

Reason (R): Amoeba employs temporary finger-like extensions for food uptake, while Paramoecium utilizes cilia to direct food to a specific intake spot.

Answer: (A)

Explanation: Both the assertion and the reason are true, and the reason correctly explains the assertion. The assertion states there’s variation, and the reason provides two distinct examples (Amoeba and Paramoecium) from the source that clearly illustrate this variation in food acquisition methods.

Assertion (A): The efficiency of food collection in unicellular organisms is directly proportional to their cell surface area.

Reason (R): In Paramoecium, cilia covering the entire surface move food to a specific spot, indicating an advanced food collection mechanism compared to generalized surface intake.

Answer: (B)

Explanation: Both the assertion and the reason are true, but the reason is not the correct explanation of the assertion. While surface area is relevant for diffusion, the assertion about direct proportionality isn’t explicitly stated or implied as a universal rule for efficiency of collection across all unicellulars. The reason accurately describes Paramoecium’s cilia function. However, Paramoecium’s specialized method (R) doesn’t directly explain why efficiency is proportional to surface area (A); rather, it shows how a definite shape requires a different strategy.

Assertion (A): All substances taken into Amoeba’s food-vacuole are immediately absorbed into the cytoplasm without further processing.

Reason (R): Inside the food-vacuole, complex substances are broken down into simpler ones which then diffuse into the cytoplasm.

Answer: (D)

Explanation: The assertion is false. The source indicates that complex substances are broken down inside the food-vacuole before they diffuse into the cytoplasm. The reason is true, accurately describing the digestion and absorption process within Amoeba.

Assertion (A): Amoeba takes in food using temporary finger-like extensions.

Reason (R): These temporary extensions are permanent structures of the cell membrane, ensuring continuous food capture.

Answer: (C)

Explanation: The assertion is true; Amoeba uses “temporary finger-like extensions” to take in food. The reason, however, is false as these extensions are explicitly described as “temporary”, not permanent structures ensuring continuous capture.

Assertion (A): The expulsion of undigested waste is a final and necessary step in the nutritional process of Amoeba.

Reason (R): The remaining undigested material is moved to the surface of the cell and then discarded.

Answer: (A)

Explanation: Both the assertion and the reason are true, and the reason correctly explains how this necessary step occurs. The source details the entire process from intake to digestion, diffusion, and finally, that “The remaining undigested material is moved to the surface of the cell and thrown out”, indicating it as the final stage of nutritional processing.

Assertion (A): The key difference in nutritional intake between Amoeba and Paramoecium primarily relates to their method of locomotion.

Reason (R): Amoeba uses temporary extensions for food intake, while Paramoecium uses cilia to direct food to a specific spot.

Answer: (D)

Explanation: The assertion is false. While both organisms have different locomotion (pseudopodia for Amoeba, cilia for Paramoecium), the source focuses on their distinct food intake mechanisms as the primary difference related to nutrition. The reason is true, accurately stating the different food intake mechanisms for Amoeba and Paramoecium.

Assertion (A): Nutritional processes in unicellular organisms are inherently more complex than those in multicellular organisms due to the lack of specialized organs.

Reason (R): In multicellular organisms, different body parts become specialized to perform distinct functions as complexity increases.

Answer: (B) Explanation: Both the assertion and the reason are true, but the reason is not the correct explanation of the assertion. The assertion is false; unicellular organisms generally have simpler nutritional processes precisely because they lack specialized organs and rely on basic cellular mechanisms. The reason is true, stating the principle of specialization in more complex organisms. The reason describes a characteristic of multicellular organisms that makes their processes more complex, not why unicellular processes are more complex.

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Heterotrophic Nutrition 

Assertion and Reason Questions on Heterotrophic Nutritional Strategies

Instructions: For each question, two statements are given: an Assertion (A) and a Reason (R). Choose the correct option from the following:

• (A) Both A and R are true, and R is the correct explanation of A.
• (B) Both A and R are true, but R is not the correct explanation of A.
• (C) A is true, but R is false.
• (D) A is false, but R is true.

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1. Question:

Assertion (A): The diverse forms of heterotrophic nutrition observed across different organisms reflect their specific adaptations to environmental conditions.

Reason (R): An organism’s nutritional strategy is influenced by the type and availability of food, as well as how it is obtained.

Answer: (A)

Explanation: Assertion (A) is true because the source states, “Each organism is adapted to its environment”, and there is “a range of strategies”. Reason (R) is also true as it directly lists the factors that determine this adaptation and variation: “The form of nutrition differs depending on the type and availability of food material as well as how it is obtained by the organism”. Reason (R) accurately explains why diverse forms of nutrition exist, linking them to environmental factors and methods of acquisition, thereby supporting the assertion of adaptation.

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2. Question:

Assertion (A): Fungi, like yeast, are unique among heterotrophs for absorbing nutrients after external digestion.

Reason (R): The body design of fungi prevents the internal breakdown of complex food materials.

Answer: (B) Explanation: Assertion (A) is true. The source explicitly states that some organisms, giving examples of fungi like yeast, “break-down the food material outside the body and then absorb it”, which is distinct from others that “take in whole material and break it down inside their bodies”. Reason (R) is also true in a general biological context regarding fungal physiology, as their cellular structure often limits internal ingestion of large particles. However, the provided source only states that “What can be taken in and broken down depends on the body design and functioning”, but does not explicitly state that the body design of fungi prevents internal breakdown. Therefore, while both statements are true, the reason is not directly supported as the explanation.

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3. Question:

Assertion (A): The body design and functioning of an organism dictate what can be taken in and broken down internally.

Reason (R): All organisms that take in whole material have the same digestive processes, regardless of their body design.

Answer: (C) Explanation: Assertion (A) is true. The chapter clearly states, “What can be taken in and broken down depends on the body design and functioning”. Reason (R) is false. The chapter emphasizes that “What can be taken in and broken down depends on the body design and functioning”, implying that digestive processes would indeed vary based on body design, not remain the same.

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4. Question:

Assertion (A): Organisms adopting a parasitic nutritive strategy typically consume whole food material and break it down inside their bodies.

Reason (R): Cuscuta (amar-bel) is an example of an organism that derives nutrition from plants without killing them.

Answer: (D) Explanation: Assertion (A) is false. The source defines parasitic nutrition as deriving “nutrition from plants or animals without killing them”. This is a distinct strategy from those that “take in whole material and break it down inside their bodies”. Reason (R) is true. Cuscuta (amar-bel) is specifically listed as an example of an organism using this parasitic strategy.

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5. Question:

Assertion (A): The diverse ways organisms obtain food underscore their unique adaptations to their ecological niches.

Reason (R): The method of obtaining food is a key factor influencing the specific nutritional strategy employed by an organism.

Answer: (A) Explanation: Assertion (A) is true, as the source highlights that organisms are adapted to their environment and the form of nutrition differs based on how food is obtained. Reason (R) is also true, as “how it is obtained by the organism” is explicitly mentioned as a factor influencing nutrition. Reason (R) directly explains Assertion (A) by outlining one of the primary drivers behind the diverse adaptations and resulting nutritional strategies.

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6. Question:

Assertion (A): Bread moulds utilize a unique method of acquiring nutrients by breaking down food outside their cellular structure.

Reason (R): This external digestion allows bread moulds to absorb pre-digested complex organic compounds efficiently.

Answer: (B) Explanation: Assertion (A) is true. The source states that “Some organisms break-down the food material outside the body and then absorb it. Examples are fungi like bread moulds”. Reason (R) is also true, as the purpose of external breakdown is indeed to make complex compounds absorbable. However, Reason (R) describes the outcome or mechanism of the external digestion mentioned in Assertion (A), rather than providing the fundamental reason or explanation for why bread moulds employ this specific unique method.

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7. Question:

Assertion (A): The availability of food material significantly influences the specific heterotrophic nutritional strategy adopted by an organism.

Reason (R): A cow’s nutritive apparatus is primarily adapted for capturing and digesting mobile food sources like deer.

Answer: (C) Explanation: Assertion (A) is true. The source explicitly states that “The form of nutrition differs depending on the type and availability of food material”. Reason (R) is false. The source contrasts a cow’s nutrition (related to “stationary (such as grass)”) with a lion’s (related to “mobile (such as a deer)”), indicating that a cow’s apparatus is adapted for stationary food, not mobile prey.

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8. Question:

Assertion (A): Ticks are examples of organisms that consume their host entirely to derive maximum nutrition.

Reason (R): Parasitic nutrition involves deriving nutrients from a living host without causing its immediate demise.

Answer: (D) Explanation: Assertion (A) is false. Ticks are listed as examples of parasitic organisms, and the parasitic strategy is defined as deriving nutrition “without killing them”. Therefore, they do not consume their host entirely. Reason (R) is true. This statement is a direct definition of parasitic nutrition provided in the source.

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9. Question:

Assertion (A): Organisms that take in whole material must have a body design capable of internal breakdown.

Reason (R): The ability to break down food inside the body is directly dependent on the organism’s inherent body design and functioning.

Answer: (A) Explanation: Assertion (A) is true. The source states, “Others take in whole material and break it down inside their bodies. What can be taken in and broken down depends on the body design and functioning”. This implies that a capable body design is necessary. Reason (R) is also true, as it is a direct quote from the source explaining the condition for internal breakdown. Reason (R) thus serves as the correct explanation for Assertion (A).

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10. Question:

Assertion (A): Mushrooms are heterotrophic organisms that break down food material outside their bodies before absorption.

Reason (R): This external digestion process is a form of saprophytic nutrition, enabling them to thrive on decaying organic matter.

Answer: (B) Explanation: Assertion (A) is true. Mushrooms are listed as fungi that “break-down the food material outside the body and then absorb it”. Reason (R) is biologically true (saprophytic nutrition is a specific type of external digestion often associated with decaying matter), but the source does not use the term “saprophytic” or explicitly state that their external digestion enables them to thrive on “decaying organic matter”. While R is true, it introduces information not directly supported or explained by the provided text as the reason for A. Therefore, it is not the correct explanation from the source’s context.

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11. Question:

Assertion (A): The availability of food material is a crucial factor influencing an organism’s heterotrophic nutritional strategy.

Reason (R): The method of obtaining food, such as grazing or hunting, is irrelevant once the food material is available.

Answer: (C) Explanation: Assertion (A) is true. The source explicitly states that “The form of nutrition differs depending on the type and availability of food material”. Reason (R) is false. The source also states that “how it is obtained by the organism” is a factor influencing the form of nutrition, and uses examples like a cow (grazing) and a lion (hunting) to illustrate this point. Therefore, the method of obtaining food is highly relevant.

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12. Question:

Assertion (A): Leeches are heterotrophs that consume whole blood meals and digest them internally, similar to a lion eating a deer.

Reason (R): The parasitic strategy allows organisms to obtain nutrition from plants or animals without causing the host’s death.

Answer: (D) Explanation: Assertion (A) is false. Leeches are listed as examples of organisms employing a “parasitic nutritive strategy”, which is distinct from taking in “whole material” like a lion. Parasites derive nutrition “without killing them”, which implies a non-consumptive relationship of the host’s entire body. Reason (R) is true. This statement directly defines the parasitic nutritive strategy as given in the source.

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13. Question:

Assertion (A): Heterotrophic nutrition encompasses a wide array of strategies to acquire and utilize food.

Reason (R): The specific strategy employed by an organism is intricately linked to its environmental adaptations and the nature of its food source.

Answer: (A) Explanation: Assertion (A) is true. The source states, “There is a range of strategies by which the food is taken in and used by the organism”. Reason (R) is also true, as “Each organism is adapted to its environment. The form of nutrition differs depending on the type and availability of food material as well as how it is obtained by the organism”. Reason (R) directly explains the broad “range of strategies” mentioned in Assertion (A) by highlighting the underlying adaptive and environmental influences.

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14. Question:

Assertion (A): Organisms that absorb pre-digested food material do not require initial internal enzymatic breakdown of complex substances.

Reason (R): Fungi like bread moulds secrete enzymes externally to break down complex food into simpler absorbable forms.

Answer: (B) Explanation: Assertion (A) is true. The source explains that these organisms “break-down the food material outside the body and then absorb it”, meaning the initial complex breakdown happens externally, not internally. Reason (R) is true, as the “break-down” mentioned in the source for fungi (like bread moulds) implies the use of enzymes for external digestion. However, Reason (R) describes how the external digestion occurs, which leads to Assertion (A), but it doesn’t explain why these organisms evolved this particular strategy or why they do not require internal enzymatic breakdown from the onset of ingestion.

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15. Question:

Assertion (A): Organisms that take in whole food material rely on their body design and functioning for internal breakdown.

Reason (R): This internal breakdown strategy is exclusively found in organisms that consume animal sources.

Answer: (C) Explanation: Assertion (A) is true. The source explicitly states, “Others take in whole material and break it down inside their bodies. What can be taken in and broken down depends on the body design and functioning”. Reason (R) is false. The source gives a cow (which eats grass, a plant source) as an example of an organism whose nutritive apparatus handles a specific food type, implying it takes in whole material for internal breakdown, thus not exclusively for animal sources.

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16. Question:

Assertion (A): Yeast directly ingests whole food particles and breaks them down inside its cells.

Reason (R): Yeast is a fungus that obtains nutrition by breaking down food material outside its body and then absorbing it.

Answer: (D) Explanation: Assertion (A) is false. Yeast is an example of a fungus, and fungi are described as organisms that “break-down the food material outside the body and then absorb it”, not ingest whole material and break it down internally. Reason (R) is true. This statement accurately describes the nutritional strategy of yeast as a fungus according to the source.

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17. Question:

Assertion (A): The body design and functioning of an organism are critical determinants of its ability to take in and process food.

Reason (R): The range of materials an organism can utilize as food directly depends on its inherent physiological and anatomical adaptations.

Answer: (A) Explanation: Assertion (A) is true. The source states, “What can be taken in and broken down depends on the body design and functioning”. Reason (R) is also true. The “body design and functioning” represent the organism’s physiological and anatomical adaptations, and these directly determine “what can be taken in and broken down,” which refers to the range of food materials. Reason (R) clarifies and explains Assertion (A) by using slightly different terminology that conveys the same meaning.

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18. Question:

Assertion (A): Organisms like bread moulds and mushrooms perform extracellular digestion.

Reason (R): Their method of nutrient acquisition involves releasing digestive enzymes onto the food material before absorption.

Answer: (B) Explanation: Assertion (A) is true. The source describes fungi (including bread moulds and mushrooms) as organisms that “break-down the food material outside the body and then absorb it”. “Extracellular digestion” is the scientific term for this process. Reason (R) is also true, as the “break-down” of food material outside the body necessarily involves the release of digestive enzymes. However, Reason (R) describes the mechanism by which extracellular digestion (Assertion A) occurs, rather than providing the ultimate reason or explanation for why they employ this specific nutritional strategy.

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19. Question:


Assertion (A): The type of food material, such as stationary or mobile, directly impacts the design of an organism’s nutritive apparatus.

Reason (R): The cow and the lion have identical nutritive apparatuses because they are both heterotrophs.

Answer: (C) Explanation: Assertion (A) is true. The source explicitly states, “whether the food source is stationary (such as grass) or mobile (such as a deer), would allow for differences in how the food is accessed and what is the nutritive apparatus used by a cow and a lion”. Reason (R) is false. The source directly contradicts this by mentioning “differences in…the nutritive apparatus used by a cow and a lion” based on their food sources, implying their apparatuses are not identical.

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20. Question:

Assertion (A): The primary advantage of taking in whole food material is that it requires no prior external processing by the organism itself.

Reason (R): Organisms such as yeast employ a strategy where food material is broken down externally before absorption.

Answer: (D) Explanation: Assertion (A) is false. The source describes “take in whole material and break it down inside their bodies” but does not discuss “primary advantages” or imply a comparative simplicity. Reason (R) is true. Yeast is a fungus, and the source explicitly states that fungi “break-down the food material outside the body and then absorb it”.

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21. Question:

Assertion (A): The existence of diverse heterotrophic nutritional strategies highlights the principle of adaptation in biology.

Reason (R): Each organism’s unique way of obtaining and utilizing food is a direct result of its specific adaptation to its environment.

Answer: (A) Explanation: Assertion (A) is true. The source begins by stating “Each organism is adapted to its environment” and then discusses the “range of strategies” for nutrition, indicating a direct link. Reason (R) is also true, as the source links the “form of nutrition” to environmental factors and how food is obtained, which are all aspects of adaptation. Reason (R) precisely explains why diverse strategies (Assertion A) are observed, as they are outcomes of specific environmental adaptations.

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22. Question:

Assertion (A): Tape-worms obtain nutrition by drawing directly from the host’s digested nutrients without consuming whole material.

Reason (R): The parasitic strategy, as seen in tape-worms, focuses on sustaining the host for long-term nutrient supply.

Answer: (B)
Explanation: Assertion (A) is true. Tape-worms are listed as examples of parasitic organisms, which “derive nutrition from plants or animals without killing them”. This implies a direct absorption from the host’s systems rather than consuming “whole material” in the manner of other heterotrophs. Reason (R) is also true. The characteristic of “without killing them” implies a strategy for long-term nutrient supply from a living host. However, Reason (R) explains the purpose or consequence of the parasitic strategy, not specifically how tapeworms obtain nutrients or why they don’t consume whole material (Assertion A).

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23. Question:

Assertion (A): The specific characteristics of how food is obtained by an organism play a significant role in defining its nutritional strategy.

Reason (R): The only distinction in obtaining food highlighted by the source is whether the food source is stationary or mobile.

Answer: (C) Explanation: Assertion (A) is true. The source clearly states that “how it is obtained by the organism” is a factor influencing the form of nutrition, and contrasts strategies like external breakdown versus taking in whole material. Reason (R) is false. While the stationary/mobile distinction is an example of “how it is obtained”, the source also describes other key distinctions like breaking down food outside the body versus taking it in whole, which are also ways “how it is obtained.” Therefore, it’s not the only distinction mentioned.

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24. Question:

Assertion (A): Ticks are organisms that break down food material outside their bodies and then absorb it.

Reason (R): Ticks are parasitic organisms that derive nutrition from animals without killing them.

Answer: (D) Explanation: Assertion (A) is false. Ticks are listed as examples of parasitic organisms. The source differentiates parasitic organisms from fungi which “break-down the food material outside the body and then absorb it”. Ticks are ectoparasites that feed on blood, which they take in internally, not externally digest. Reason (R) is true. This statement correctly describes ticks and the parasitic strategy as defined in the source.

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25. Question:

Assertion (A): The survival of a parasitic organism is often dependent on the continued survival of its host.

Reason (R): Parasitic nutritive strategy is characterized by deriving nutrition from plants or animals without killing them.

Answer: (A) Explanation: Assertion (A) is true. This is a logical and fundamental implication of the parasitic strategy as defined in the source. If the host is killed, the parasite loses its source of nutrition and habitat. Reason (R) is true. This is the direct definition of parasitic nutrition provided in the source. Reason (R) explains Assertion (A) because the defining characteristic of not killing the host directly implies a reliance on the host’s continued existence for the parasite’s own survival.

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Nutrition In Human Beings 

For each question, the options are:

• (A) Both Assertion (A) and Reason (R) are true, and Reason (R) is the correct explanation of Assertion (A).
• (B) Both Assertion (A) and Reason (R) are true, but Reason (R) is NOT the correct explanation of Assertion (A).
• (C) Assertion (A) is true, but Reason (R) is false.
• (D) Assertion (A) is false, but Reason (R) is true.

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Assertion (A): The alimentary canal has various specialized regions to perform distinct functions.

Reason (R): Food must be processed into small particles of the same texture to ensure its smooth passage through the soft lining of the canal.

Assertion (A): Saliva is primarily responsible for the initial chemical digestion of proteins in the mouth.

Reason (R): Saliva contains an enzyme called salivary amylase that breaks down starch into simple sugar.

Assertion (A): Peristaltic movements are crucial for the regulated movement of food along the digestive tube.

Reason (R): These movements are characterized by the rhythmic contractions of the muscles lining the alimentary canal.

Assertion (A): The muscular walls of the stomach play a vital role in thoroughly mixing food with digestive juices.

Reason (R): This mixing ensures that the acidic medium, created by hydrochloric acid, reaches all food particles, thereby facilitating the efficient action of the enzyme pepsin.

Assertion (A): Mucus secreted in the stomach protects its inner lining from the strong action of hydrochloric acid.

Reason (R): Gastric glands present in the stomach wall are responsible for releasing hydrochloric acid, pepsin, and mucus.

Assertion (A): The small intestine is designated as the primary site for the complete digestion of carbohydrates, proteins, and fats.

Reason (R): It receives essential secretions from both the liver (bile juice) and the pancreas (pancreatic juice), which are vital for this comprehensive digestive process.

Assertion (A): Herbivores, such as those eating grass, require a significantly longer small intestine.

Reason (R): Meat is comparatively easier to digest, which is why carnivores like tigers possess a shorter small intestine.

Assertion (A): Bile juice, secreted by the liver, makes the acidic food arriving from the stomach alkaline.

Reason (R): This alkalinity is a necessary condition for the pancreatic enzymes to act effectively on the food.

Assertion (A): Bile salts are critical for increasing the efficiency of enzyme action on fats in the small intestine.

Reason (R): They achieve this by breaking down large fat globules into smaller ones, a process similar to the emulsifying action of soaps.

Assertion (A): The enzymes present in the small intestine walls finally convert complex carbohydrates into glucose

Reason (R): This conversion is primarily carried out by the enzyme lipase found in pancreatic juice

Assertion (A): The inner lining of the small intestine features numerous finger-like projections called villi, which dramatically increase the surface area for absorption.

Reason (R): The villi are richly supplied with blood vessels that transport the absorbed food to every cell of the body.

Assertion (A): Unabsorbed food material from the small intestine is directed into the large intestine.

Reason (R): The primary function of the large intestine’s wall is to absorb additional water from this material.

Assertion (A): The exit of waste material from the body is precisely regulated by the anal sphincter.

Reason (R): This sphincter muscle also controls the release of food in small amounts from the stomach into the small intestine.

Assertion (A): For food to be effectively absorbed from the alimentary canal, it must be broken down into smaller molecules.

Reason (R): This breakdown into smaller molecules is primarily accomplished through the crushing action of teeth in the mouth.

Assertion (A): The muscular tongue efficiently mixes food thoroughly with saliva during chewing.

Reason (R): Saliva contains salivary amylase, an enzyme that initiates the digestion of starch.

Assertion (A): The stomach expands upon receiving food, and its muscular walls actively mix the contents.

Reason (R): This mechanical mixing is critical to ensure that hydrochloric acid and pepsin effectively interact with the food for proper protein digestion.

Assertion (A): The phenomenon of the mouth “watering” when we desire food is exclusively due to the secretion of pure water for wetting.

Reason (R): This fluid, known as saliva, is secreted by the salivary glands and also contains digestive enzymes.

Assertion (A): The small intestine’s extensive coiling allows it to occupy a compact space despite being the longest part of the alimentary canal.

Reason (R): This compact arrangement is necessary because the small intestine is the primary site where absorbed food is transported to every cell of the body for utilization.

Assertion (A): Digested food absorbed by the walls of the small intestine is transported to every cell of the body via blood vessels.

Reason (R): The absorbed food is utilized by body cells solely for the purpose of building new tissues and repairing old ones.

Assertion (A): Enzymes are biological catalysts crucial for breaking down complex food molecules into smaller, absorbable units.

Reason (R): Enzymes generally function by creating an acidic medium, which then facilitates specific chemical reactions.

Assertion (A): The food entering the small intestine from the stomach is alkaline due to the action of bile juice.

Reason (R): The acidic nature of food leaving the stomach is due to the presence of protein-digesting enzymes.

Assertion (A): The food coming from the stomach is acidic and needs to be made alkaline for pancreatic enzymes to act.

Reason (R): Bile juice from the liver makes this acidic food alkaline.

Assertion (A): Pancreatic juice is crucial as it contains a variety of enzymes vital for digestion.

Reason (R): It specifically contains trypsin for protein digestion and lipase for breaking down emulsified fats.

Assertion (A): Because the lining of the alimentary canal is soft, food is wetted to ensure its smooth passage.

Reason (R): This wetting process, along with crushing, also ensures that the food particles are of the same texture.

Assertion (A): Gastric glands release a protein-digesting enzyme called pepsin.

Reason (R): Pepsin functions most effectively in an alkaline environment within the stomach.

Assertion (A): The entire process of digestion involves breaking down complex food molecules into much smaller ones.

Reason (R): This molecular breakdown is essential because the absorbed smaller molecules are subsequently utilized by the body’s cells for obtaining energy, building new tissues, and repairing old ones.

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Nutrition 

General Options for Assertion-Reason Questions:

• A. Both Assertion (A) and Reason (R) are true, and Reason (R) is the correct explanation of Assertion (A).
• B. Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).
• C. Assertion (A) is true, but Reason (R) is false.
• D. Assertion (A) is false, but Reason (R) is true.

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Assertion (A): The breakdown of glucose into pyruvate is the initial step common to all forms of cellular respiration.

Reason (R): This initial step takes place in the cytoplasm, independent of oxygen.

Answer: A

Explanation: Assertion (A) is true because the source states that “In all cases, the first step is the break-down of glucose… into pyruvate”. Reason (R) is also true as “This process takes place in the cytoplasm” and “some use other pathways that do not involve oxygen” after this initial step, implying its independence from oxygen at this stage. Reason (R) correctly explains why this first step is universal, as it occurs in a cellular compartment (cytoplasm) that is common to all respiration types and does not require oxygen.

Assertion (A): Diverse organisms break down food material for energy in different ways.

Reason (R): Some organisms use oxygen, while others employ pathways that do not involve oxygen.

Answer: B

Explanation: Assertion (A) is true, as the source mentions, “Diverse organisms do this in different ways”. Reason (R) is also true, stating that “some use oxygen to break-down glucose completely… some use other pathways that do not involve oxygen”. However, Reason (R) describes the diversity rather than explaining the fundamental reason for the existence of diverse pathways (e.g., evolutionary adaptation or environmental niches). Therefore, both are true, but R is not the correct explanation of A.

Assertion (A): The energy released in aerobic respiration is significantly greater than in anaerobic respiration.

Reason (R): Aerobic respiration produces lactic acid as a byproduct, which is less energy-efficient.

Answer: C

Explanation: Assertion (A) is true because the source states, “The release of energy in this aerobic process is a lot greater than in the anaerobic process”. Reason (R) is false. Lactic acid is a product of anaerobic respiration in muscle cells, not aerobic respiration. Aerobic respiration breaks down pyruvate to carbon dioxide and water.

Assertion (A): The build-up of ethanol in human muscle cells during sudden activity causes cramps.

Reason (R): Lactic acid accumulation in muscle cells occurs when there is a lack of oxygen.

Answer: D

Explanation: Assertion (A) is false. The source clearly states that “This build-up of lactic acid in our muscles during sudden activity causes cramps”. Ethanol production occurs in yeast during fermentation, not in human muscle cells. Reason (R) is true, as the source explains, “when there is a lack of oxygen in our muscle cells… the pyruvate is converted into lactic acid”.

Assertion (A): ATP is used immediately to fuel various endothermic reactions within a cell.

Reason (R): The energy released during cellular respiration is first used to synthesize ATP, which then provides a fixed amount of energy upon breakdown for cellular activities.

Answer: A

Explanation: Assertion (A) is true, as ATP is “used to fuel all other activities in the cell” and “can drive the endothermic reactions”. Reason (R) is also true, stating that “The energy released during cellular respiration is immediately used to synthesise a molecule called ATP” and “ATP is broken down giving rise to a fixed amount of energy”. Reason (R) comprehensively explains how ATP functions as the cell’s energy currency to drive endothermic reactions.

Assertion (A): Plants exchange gases like carbon dioxide and oxygen through stomata, and these gases diffuse through large inter-cellular spaces.

Reason (R): The direction of gas diffusion in plants depends upon the environmental conditions and the requirements of the plant.

Answer: B

Explanation: Assertion (A) is true, as plants “exchange gases through stomata, and the large inter-cellular spaces ensure that all cells are in contact with air”. Reason (R) is also true, stating, “The direction of diffusion depends upon the environmental conditions and the requirements of the plant”. However, Reason (R) explains what influences the direction of diffusion, not how the gases are exchanged through the stated structures. Therefore, both are true, but R is not the correct explanation of A.

Assertion (A): At night, plants primarily release carbon dioxide as their major gas exchange activity.

Reason (R): During the night, photosynthesis is the dominant process, consuming atmospheric carbon dioxide.

Answer: C

Explanation: Assertion (A) is true, as the source specifies, “At night, when there is no photosynthesis occurring, CO2 elimination is the major exchange activity going on”. Reason (R) is false. At night, “there is no photosynthesis occurring”, meaning CO2 is not consumed by photosynthesis.

Assertion (A): Aquatic organisms typically have a slower breathing rate than terrestrial organisms.

Reason (R): The amount of oxygen dissolved in water is fairly low compared to the amount of oxygen in the air.

Answer: D

Explanation: Assertion (A) is false. The source states, “the rate of breathing in aquatic organisms is much faster than that seen in terrestrial organisms”. Reason (R) is true, as “the amount of dissolved oxygen is fairly low compared to the amount of oxygen in the air”.

Assertion (A): The gas exchange surface in terrestrial animals is usually placed within the body.

Reason (R): This surface is very fine and delicate, requiring protection from the external environment.

Answer: A

Explanation: Assertion (A) is true, as the source indicates the surface “is usually placed within the body”. Reason (R) is also true, explaining that “this surface is very fine and delicate. In order to protect this surface, it is usually placed within the body”. Reason (R) is the direct explanation for Assertion (A).

Assertion (A): Human nostrils are lined with fine hairs and mucus to filter incoming air.

Reason (R): Rings of cartilage are present in the throat to ensure the air-passage does not collapse.

Answer: B

Explanation: Assertion (A) is true, as “The air passing through the nostrils is filtered by fine hairs that line the passage. The passage is also lined with mucus which helps in this process”. Reason (R) is also true, stating, “Rings of cartilage are present in the throat. These ensure that the air-passage does not collapse”. While both statements are true facts about the human respiratory system, Reason (R) describes a function in the throat, which does not explain the function of hairs and mucus in the nostrils.

Assertion (A): The alveoli provide a large surface area for efficient gas exchange in the lungs.

Reason (R): Alveolar walls are thick and lack extensive blood vessels to prevent excessive fluid loss.

Answer: C

Explanation: Assertion (A) is true, as “The alveoli provide a surface where the exchange of gases can take place” and their balloon-like structure contributes to a large surface area. Reason (R) is false. The source explicitly states that “The walls of the alveoli contain an extensive network of blood-vessels” and implies they are delicate for exchange. They are not described as thick, nor do they lack blood vessels for fluid prevention; rather, they are thin and highly vascularized for efficient exchange.

Assertion (A): During human inhalation, the diaphragm lifts, and the ribs flatten.

Reason (R): These actions cause the chest cavity to become larger, leading to air being sucked into the lungs.

Answer: D

Explanation: Assertion (A) is false. During inhalation, “we lift our ribs and flatten our diaphragm”. Reason (R) is true, as “the chest cavity becomes larger as a result. Because of this, air is sucked into the lungs and fills the expanded alveoli”.

Assertion (A): Lungs always contain a residual volume of air during the breathing cycle.

Reason (R): This residual volume ensures sufficient time for oxygen to be absorbed and carbon dioxide to be released.

Answer: A

Explanation: Assertion (A) is true, as “the lungs always contain a residual volume of air”. Reason (R) is also true, stating that this volume is present “so that there is sufficient time for oxygen to be absorbed and for the carbon dioxide to be released”. Reason (R) provides the direct explanation for the presence of residual volume.

Assertion (A): Respiratory pigments are essential for efficient oxygen delivery in large animals.

Reason (R): Haemoglobin, the respiratory pigment in human beings, has a very high affinity for oxygen.

Answer: B

Explanation: Assertion (A) is true because “When the body size of animals is large, the diffusion pressure alone cannot take care of oxygen delivery… Instead, respiratory pigments take up oxygen”. Reason (R) is also true about haemoglobin’s affinity for oxygen. However, Reason (R) describes a specific property of one pigment, not the general necessity of pigments for large animals, which is due to diffusion limitations. Therefore, both are true, but R is not the correct explanation of A.

Assertion (A): Haemoglobin helps in the transport of oxygen from the lungs to the body tissues.

Reason (R): Carbon dioxide is primarily transported to the lungs bound to haemoglobin.

Answer: C

Explanation: Assertion (A) is true, as “respiratory pigments take up oxygen from the air in the lungs and carry it to tissues… In human beings, the respiratory pigment is haemoglobin which has a very high affinity for oxygen”. Reason (R) is false. The source states, “Carbon dioxide is more soluble in water than oxygen is and hence is mostly transported in the dissolved form in our blood”.

Assertion (A): All cells in a plant directly exchange gases with the outside air through stomata.

Reason (R): Large inter-cellular spaces ensure that all cells are in contact with air for gas exchange.

Answer: D

Explanation: Assertion (A) is false. While plants exchange gases through stomata, the gases then move through “large inter-cellular spaces” to reach “all cells”. Cells don’t directly contact outside air; they contact the air within these spaces. Reason (R) is true and accurately describes the role of intercellular spaces.

Assertion (A): Oxygen is required for the complete breakdown of glucose into carbon dioxide and water.

Reason (R): This process, known as aerobic respiration, takes place in the mitochondria.

Answer: A

Explanation: Assertion (A) is true, as the source states, “some use oxygen to break-down glucose completely into carbon dioxide and water”. Reason (R) is also true, specifying that “Break-down of pyruvate using oxygen takes place in the mitochondria. This process… is called aerobic respiration”. Reason (R) explains where this oxygen-dependent complete breakdown occurs, directly supporting A.

Assertion (A): Fishes use gills to take up oxygen dissolved in water.

Reason (R): The rate of breathing in aquatic organisms is much faster than that seen in terrestrial organisms.

Answer: B

Explanation: Assertion (A) is true, as “Fishes take in water through their mouths and force it past the gills where the dissolved oxygen is taken up by blood”. Reason (R) is also true, as “the rate of breathing in aquatic organisms is much faster than that seen in terrestrial organisms”. However, Reason (R) describes a characteristic of aquatic respiration, not how gills function to take up oxygen. Therefore, both are true, but R is not the correct explanation of A.

Assertion (A): Plants only release oxygen during daylight hours.

Reason (R): During the day, carbon dioxide elimination is the major exchange activity in plants.

Answer: C

Explanation: Assertion (A) is true, as “During the day, CO2 generated during respiration is used up for photosynthesis, hence there is no CO2 release. Instead, oxygen release is the major event at this time”. Reason (R) is false. Carbon dioxide elimination is the major exchange activity at night, not during the day.

Assertion (A): Respiration is the process of taking in food material to provide energy.

Reason (R): The food material taken in during the process of nutrition is used in cells to provide energy for various life processes.

Answer: D

Explanation: Assertion (A) is false. Respiration is the process where “food material taken in during the process of nutrition is used in cells to provide energy”. Nutrition is the process of taking in food. Reason (R) is true and correctly describes the role of food material in respiration.

Assertion (A): The alveoli contain an extensive network of blood-vessels.

Reason (R): This extensive network provides a large surface area for efficient exchange of gases between the air in the alveoli and the blood.

Answer: A

Explanation: Assertion (A) is true, as “The walls of the alveoli contain an extensive network of blood-vessels”. Reason (R) is also true and explains the significance of this network, stating that the alveoli “provide a surface where the exchange of gases can take place” with blood. The extensive network maximizes the contact for efficient gas exchange.

Assertion (A): The structure of respiratory organs in terrestrial animals increases surface area.

Reason (R): This increased surface area is necessary because oxygen exchange has to take place across a very fine and delicate surface.

Answer: B

Explanation: Assertion (A) is true, as “All these organs have a structure that increases the surface area which is in contact with the oxygen-rich atmosphere”. Reason (R) is also true, as “the exchange of oxygen and carbon dioxide has to take place across this surface, this surface is very fine and delicate”. While the delicacy is a characteristic of the surface, it doesn’t directly explain why the surface area needs to be increased; rather, the large surface area compensates for the delicate and often internal nature of the surface to facilitate sufficient gas exchange.

Assertion (A): Diffusion alone is insufficient for oxygen delivery to all parts of a large animal’s body.

Reason (R): This is because respiratory pigments decrease the efficiency of oxygen transport.

Answer: C

Explanation: Assertion (A) is true, as “When the body size of animals is large, the diffusion pressure alone cannot take care of oxygen delivery to all parts of the body”. Reason (R) is false. Respiratory pigments like haemoglobin increase the efficiency of oxygen transport, as they “take up oxygen… and carry it to tissues which are deficient in oxygen before releasing it”.

Assertion (A): Carbon dioxide is transported in human blood only bound to haemoglobin.

Reason (R): Carbon dioxide is more soluble in water than oxygen and is mostly transported in the dissolved form in our blood.

Answer: D

Explanation: Assertion (A) is false. The source states that “Carbon dioxide is more soluble in water than oxygen is and hence is mostly transported in the dissolved form in our blood”. Reason (R) is true and directly supports the method of CO2 transport.

Assertion (A): The expanded alveoli during inhalation are crucial for efficient gas exchange.

Reason (R): Air is sucked into the lungs, filling the expanded alveoli, allowing blood to release CO2 and take up O2.

Answer: A

Explanation: Assertion (A) is true, as the expansion of alveoli allows them to fill with air, providing the surface for gas exchange. Reason (R) is also true, explaining the mechanics of how the alveoli expand and how gases are exchanged once filled: “air is sucked into the lungs and fills the expanded alveoli. The blood brings carbon dioxide… for release… and the oxygen in the alveolar air is taken up by blood”. Reason (R) directly explains the mechanism facilitated by the expanded alveoli for gas exchange.

Transportation In Human Beings

Options for Assertion and Reason Questions: (A) Both Assertion (A) and Reason (R) are true, and Reason (R) is the correct explanation of Assertion (A). (B) Both Assertion (A) and Reason (R) are true, but Reason (R) is NOT the correct explanation of Assertion (A). (C) Assertion (A) is true, but Reason (R) is false. (D) Assertion (A) is false, but Reason (R) is true.

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Assertion (A): The muscular walls of ventricles are thicker than those of the atria.

Reason (R): Ventricles have to pump blood into various organs, requiring more force than the atria, which primarily collect blood.

Answer: (A)

Explanation: Both statements are true and directly supported by the source. The ventricles, especially the left ventricle, need to generate significant pressure to pump blood to the entire body, or to the lungs, hence their thicker, more muscular walls compared to the atria, which only collect blood and pump it to the ventricles.

1. Assertion (A): The heart has different chambers to prevent oxygen-rich blood from mixing with blood containing carbon dioxide.
   
   Reason (R): Mixing of oxygenated and deoxygenated blood streams allows for a highly efficient supply of oxygen to the body.
   
   • Answer: (C)
   • Explanation: Assertion (A) is true. The separation of chambers prevents mixing of oxygenated and deoxygenated blood. Reason (R) is false; the source states that separation (not mixing) allows for a highly efficient supply of oxygen. Mixing would reduce efficiency.

1. Assertion (A): In fishes, blood goes through the heart only once during one cycle of passage through the body.
   
   Reason (R): Fishes have only two chambers in their hearts, and blood is pumped directly from the gills to the rest of the body after oxygenation.
   
   • Answer: (A)
   • Explanation: Both Assertion (A) and Reason (R) are true. The two-chambered heart in fishes pumps blood to the gills for oxygenation, and then the oxygenated blood flows directly to the body, completing a single circuit through the heart, which is known as single circulation. Reason (R) accurately explains this process.

1. Assertion (A): Arteries have thick, elastic walls.
   
   Reason (R): They collect blood from different organs and bring it back to the heart where the pressure is no longer high.
   
   • Answer: (C)
   • Explanation: Assertion (A) is true; arteries do have thick, elastic walls because blood emerges from the heart under high pressure. However, Reason (R) is false; veins, not arteries, collect blood from different organs and bring it back to the heart, and they do so when the blood is no longer under high pressure.

1. Assertion (A): Platelet cells help to clot blood at injury points.
   
   Reason (R): This clotting process is primarily to ensure that blood flows only in one direction in veins.
   
   • Answer: (C)
   • Explanation: Assertion (A) is true; platelet cells circulate and plug leaks by helping blood to clot at injury points. Reason (R) is false; the purpose of clotting is to minimize blood loss and prevent a loss of pressure from the system. Valves, not platelets, ensure that blood flows only in one direction in veins.

1. Assertion (A): Lymph is similar to the plasma of blood but is colourless and contains less protein.
   
   Reason (R): Lymph drains into lymphatic capillaries from intercellular spaces, and it carries digested and absorbed fat from the intestine.
   
   • Answer: (B)
   • Explanation: Both Assertion (A) and Reason (R) are true statements about lymph. However, Reason (R) describes some functions and drainage pathways of lymph, while Assertion (A) describes its composition. Reason (R) does not explain why lymph has the specific composition described in Assertion (A) (i.e., why it’s colourless or has less protein).

1. Assertion (A): Exchange of material between the blood and surrounding cells primarily occurs across the walls of capillaries.
   
   Reason (R): Capillary walls are one-cell thick, facilitating efficient diffusion of substances.
   
   • Answer: (A)
   • Explanation: Both Assertion (A) and Reason (R) are true. The very thin, one-cell thick walls of capillaries are specifically designed to allow for the efficient exchange of materials between the blood and the tissues, making Reason (R) the correct explanation for Assertion (A).

1. Assertion (A): Plasma transports oxygen in dissolved form throughout the body.
   
   Reason (R): Red blood corpuscles are the primary carriers of oxygen in the blood.
   
   • Answer: (D)
   • Explanation: Assertion (A) is false; the source explicitly states that “Oxygen is carried by the red blood corpuscles”. Plasma transports food, carbon dioxide, and nitrogenous wastes in dissolved form. Reason (R) is true; oxygen is indeed carried by red blood corpuscles.

1. Assertion (A): Vertebrates, other than fish, exhibit double circulation where blood goes through the heart twice in one cycle.
   
   Reason (R): This is useful in animals that have high energy needs, such as birds and mammals, as it allows for a highly efficient supply of oxygen.
   
   • Answer: (A)
   • Explanation: Both Assertion (A) and Reason (R) are true. Double circulation ensures efficient oxygen supply. The separation of oxygenated and deoxygenated blood, which is part of double circulation, enables this efficiency, making it crucial for animals with high energy demands like birds and mammals to maintain body temperature.

1. Assertion (A): Valves in the heart ensure that blood does not flow backwards when the atria or ventricles contract.
   
   Reason (R): Veins also possess valves that ensure blood flows only in one direction, back towards the heart.
   
   • Answer: (B)
   • Explanation: Both Assertion (A) and Reason (R) are true statements. Valves prevent backflow in both the heart and veins. However, Reason (R) describes the function of valves in veins and does not explain why valves are necessary in the heart. These are two distinct but related facts about valves in the circulatory system.

1. Assertion (A): Veins do not require thick walls.
   
   Reason (R): By the time blood reaches the veins from various organs, it is no longer under the high pressure exerted by the heart’s pumping action.
   
   • Answer: (A)
   • Explanation: Both Assertion (A) and Reason (R) are true. The absence of high pressure in the blood as it returns to the heart is precisely why veins do not need the thick walls characteristic of arteries, which carry blood under high pressure. Reason (R) correctly explains Assertion (A).

1. Assertion (A): Amphibians and many reptiles have three-chambered hearts and can tolerate some mixing of oxygenated and de-oxygenated blood streams.
   
   Reason (R): These animals constantly use energy to maintain a constant body temperature, requiring the most efficient oxygen supply.
   
   • Answer: (C)
   • Explanation: Assertion (A) is true; amphibians and many reptiles have three-chambered hearts and tolerate some mixing. Reason (R) is false; the source states that such animals do not use energy to maintain their body temperature, and their body temperature depends on the environment. The high energy need and constant body temperature maintenance are characteristic of birds and mammals, which require highly efficient oxygen supply due to better separation of blood.

1. Assertion (A): The body needs a pumping organ, a network of tubes, and a system for repair to circulate blood effectively.
   
   Reason (R): Blood serves to transport essential substances like food, oxygen, and waste materials throughout our bodies.
   
   • Answer: (A)
   • Explanation: Both Assertion (A) and Reason (R) are true. The vital role of blood in transporting substances (R) directly necessitates the components of the circulatory system described in Assertion (A) – a pump (heart), tubes (blood vessels), and a repair mechanism (platelets).

1. Assertion (A): A leakage from the circulatory system can lead to a significant loss of pressure.
   
   Reason (R): Platelet cells actively circulate to plug these leaks, thereby preventing a reduction in the efficiency of the pumping system.
   
   • Answer: (B)
   • Explanation: Both Assertion (A) and Reason (R) are true statements. Leakage does cause a loss of pressure, and platelets do repair leaks to maintain efficiency. However, Reason (R) describes the solution or response to leakage and pressure loss, not why leakage causes pressure loss in the first place. The pressure loss is a physical consequence of the leak.

1. Assertion (A): Blood is classified as a fluid connective tissue.
   
   Reason (R): It consists of a fluid medium called plasma in which various cells are suspended, enabling it to connect and transport substances throughout the body.
   
   • Answer: (A)
   • Explanation: Both Assertion (A) and Reason (R) are true. Reason (R) provides the key characteristics (fluid medium, suspended cells, transport function) that support the classification of blood as a fluid connective tissue, thereby correctly explaining Assertion (A).

1. Assertion (A): Oxygen-rich blood from the lungs first enters the thin-walled upper chamber on the left side of the heart.
   
   Reason (R): The right ventricle pumps de-oxygenated blood to the lungs for oxygenation.
   
   • Answer: (B)
   • Explanation: Both Assertion (A) and Reason (R) are true. Oxygen-rich blood from the lungs enters the left atrium. De-oxygenated blood from the right ventricle is indeed pumped to the lungs for oxygenation. However, Reason (R) describes the pathway of deoxygenated blood to the lungs, which is a separate part of the circulatory cycle, and does not explain why oxygen-rich blood enters the left atrium first.

1. Assertion (A): Lymph is formed in the intercellular spaces in tissues.
   
   Reason (R): Lymph plays a crucial role in carrying digested and absorbed fat from the intestine to the blood.
   
   • Answer: (B)
   • Explanation: Both Assertion (A) and Reason (R) are true. Lymph forms from plasma, proteins, and blood cells escaping into intercellular spaces. It also transports absorbed fats. However, Reason (R) describes a specific function of lymph and does not explain how or why it is formed in the intercellular spaces.

1. Assertion (A): The human heart is a muscular organ that is approximately the size of our fist.
   
   Reason (R): This specific size enables the heart to transport carbon dioxide effectively throughout the body.
   
   • Answer: (C)
   • Explanation: Assertion (A) is true; the heart is a muscular organ about the size of a fist. Reason (R) is false; the source states the size of the heart and that blood transports carbon dioxide, but it does not link the heart’s size directly or primarily to the effectiveness of carbon dioxide transport. The size is a general anatomical characteristic, while carbon dioxide transport is a function of the blood.

1. Assertion (A): Blood transports food, oxygen, carbon dioxide, and nitrogenous wastes in our bodies.
   
   Reason (R): Plasma transports food, carbon dioxide, and nitrogenous wastes in dissolved form, while oxygen is carried by the red blood corpuscles.
   
   • Answer: (A)
   • Explanation: Both Assertion (A) and Reason (R) are true. Reason (R) provides the detailed breakdown of how different substances are transported by specific components of the blood, thus explaining the overall transport function stated in Assertion (A).

1. Assertion (A): Arteries carry blood away from the heart to various organs of the body.
   
   Reason (R): Veins collect blood from different organs and bring it back to the heart.
   
   • Answer: (B)
   • Explanation: Both Assertion (A) and Reason (R) are true statements. They correctly define the distinct directional functions of arteries and veins. However, Reason (R) describes the function of veins and does not explain why arteries carry blood away from the heart.

1. Assertion (A): Lymph is similar to blood plasma but is colourless and contains more protein.
   
   Reason (R): Lymph is formed when some amount of plasma, proteins, and blood cells escape into intercellular spaces from capillary walls.
   
   • Answer: (D)
   • Explanation: Assertion (A) is false; lymph is similar to plasma but contains less protein, not more. Reason (R) is true; lymph is indeed formed by the escape of plasma, proteins, and blood cells through capillary pores into intercellular spaces.

1. Assertion (A): The separation of the right and left sides of the heart is useful for providing a highly efficient supply of oxygen to the body.
   
   Reason (R): This efficiency is particularly important for animals like birds and mammals, which constantly use energy to maintain their body temperature.
   
   • Answer: (A)
   • Explanation: Both Assertion (A) and Reason (R) are true. The separation prevents mixing of oxygenated and deoxygenated blood, leading to high oxygen supply efficiency. This efficiency is essential for endothermic animals like birds and mammals because they require constant energy to maintain body temperature, making Reason (R) a correct explanation for the utility of the separation.

1. Assertion (A): Arteries divide into smaller and smaller vessels upon reaching an organ or tissue.
   
   Reason (R): This division forms capillaries, which have one-cell thick walls, bringing blood in close contact with individual cells for material exchange.
   
   • Answer: (A)
   • Explanation: Both Assertion (A) and Reason (R) are true. The division of arteries into capillaries (R) is the mechanism by which blood is brought into intimate contact with all individual cells (A) for the crucial exchange of materials, thus Reason (R) correctly explains Assertion (A).

1. Assertion (A): Blood plasma is the fluid medium in which red blood corpuscles are dissolved.
   
   Reason (R): Plasma transports nitrogenous wastes and food in dissolved form.
   
   • Answer: (D)
   • Explanation: Assertion (A) is false; red blood corpuscles are suspended in plasma, not dissolved. Reason (R) is true; plasma transports food, carbon dioxide, and nitrogenous wastes in dissolved form.

1. Assertion (A): Animals like birds and mammals have three-chambered hearts that tolerate some mixing of oxygenated and de-oxygenated blood.
   
   Reason (R): These animals constantly use energy to maintain their body temperature, requiring a highly efficient and unmixed oxygen supply.
   
   • Answer: (D)
   • Explanation: Assertion (A) is false; birds and mammals have a highly efficient system with complete separation of oxygenated and deoxygenated blood, implicitly indicating a four-chambered heart (not explicitly stated as 4 but implied by efficient separation, unlike the 3-chambered amphibians/reptiles that tolerate mixing). Reason (R) is true; birds and mammals do have high energy needs to maintain body temperature, which requires a highly efficient oxygen supply provided by complete separation of blood streams.

Transportation In Plants 

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Assertion and Reason Questions

For each of the questions below, two statements are given – one labeled Assertion (A) and the other labeled Reason (R). Select the most appropriate answer from the options provided:

• (a) Both A and R are true and R is the correct explanation of A.
• (b) Both A and R are true but R is NOT the correct explanation of A.
• (c) A is true but R is false.
• (d) A is false but R is true.

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1. Question Assertion (A): Plants have relatively low energy needs and can use slow transport systems.

Reason (R): Plants do not move, and a significant proportion of their body tissues consist of dead cells. Answer: (a) Explanation: Both the assertion and the reason are true. The low energy demands of plants, which enable the use of slow transport systems, are directly attributed to their immobility and the presence of numerous dead cells in their tissues. The reason provides the correct explanation for the assertion.

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2. Question

Assertion (A): The xylem tissue is responsible for transporting water and minerals throughout the plant body.

Reason (R): Xylem and phloem are described as independently organized conducting tubes. Answer: (b) Explanation: Both the assertion and the reason are true statements based on the sources. Xylem does transport water and minerals. It is also true that xylem and phloem are independent systems with distinct functions. However, the reason (“Xylem and phloem are independently organized…”) does not explain why xylem specifically transports water and minerals. It merely describes a characteristic of the overall plant transport system.

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3. Question

Assertion (A): Translocation, the transport of soluble products of photosynthesis, occurs in the phloem tissue.

Reason (R): Unlike water transport, translocation in phloem is largely explained by simple physical forces and does not require energy.

Answer: (c) Explanation: The assertion is true; translocation of soluble products of photosynthesis occurs in the phloem. The reason is false; translocation in phloem is achieved by utilizing energy (ATP), which is a key difference from water transport in xylem that relies on simple physical forces.

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4. Question

Assertion (A): Phloem transports products of photosynthesis only in an upward direction towards growing parts.

Reason (R): The translocation of food and other substances in phloem takes place in the sieve tubes with the help of adjacent companion cells, in both upward and downward directions.

Answer: (d) Explanation: The assertion is false. Phloem transports materials in both upward and downward directions, delivering them to storage organs (roots, fruits, seeds) and growing organs. The reason is true and accurately describes the components involved and the bidirectional nature of phloem transport.

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5. Question

Assertion (A): Water moves into the root from the soil to equalize the concentration difference of ions between the root and the soil.

Reason (R): Root cells actively take up ions, which creates this concentration difference, thereby drawing water into the root.

Answer: (a) Explanation: Both the assertion and the reason are true. The active uptake of ions by root cells creates an osmotic gradient, leading to a difference in concentration between the root and the soil. Water then moves into the root by osmosis to eliminate this difference. The reason correctly explains the mechanism described in the assertion.

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6. Question

Assertion (A): Transpiration aids in the temperature regulation of the plant body.

Reason (R): Transpiration is defined as the loss of water in the form of vapor from the aerial parts of the plant.

Answer: (b) Explanation: Both the assertion and the reason are true statements. Transpiration does help regulate temperature, and it is accurately defined as the loss of water vapor from aerial parts. However, the reason (the definition of transpiration) does not explain how it helps in temperature regulation (which is typically through evaporative cooling).

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7. Question

Assertion (A): The movement of material in the phloem always occurs from an area of lower osmotic pressure to an area of higher osmotic pressure.

Reason (R): Phloem can move material flexibly according to the plant’s needs, for example, transporting sugar from roots to buds in spring.

Answer: (c) Explanation: The assertion is false. Material in the phloem moves from tissues which have higher osmotic pressure to tissues which have less pressure. The reason is true; phloem transport is adaptable to the plant’s needs, as exemplified by sugar transport from storage to growing buds.

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8. Question

Assertion (A): Diffusion is always sufficient for the transport of raw materials and energy throughout all plant body designs.

Reason (R): Plants possess low energy needs and can thus utilize relatively slow transport systems.

Answer: (d) Explanation: The assertion is false. Diffusion is only sufficient for small plants where distances are small; for large plants with complex body designs, a proper transportation system is essential because diffusion is insufficient. The reason is true; plants do have low energy needs due to immobility and a high proportion of dead cells, allowing for slow transport systems.

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9. Question

Assertion (A): Evaporation of water molecules from the cells of a leaf creates a suction force that pulls water from the xylem of roots.

Reason (R): This suction, known as transpiration pull, becomes the major driving force in water movement in the xylem during the day when stomata are open.

Answer: (a) Explanation: Both the assertion and the reason are true. The evaporation of water from leaves creates a suction (transpiration pull). This transpiration pull is indeed the primary force driving water movement in the xylem during the day, especially when stomata are open. The reason explains the significance and timing of this process.

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10. Question

Assertion (A): Products of photosynthesis are transported from the leaves to other parts of the plant via the phloem.

Reason (R): Phloem tissue transports not only products of photosynthesis but also amino acids and other substances.

Answer: (b) Explanation: Both the assertion and the reason are true. The phloem does transport photosynthetic products from leaves. It is also true that phloem transports amino acids and other substances. However, the fact that phloem carries other substances (reason) does not explain why it transports photosynthetic products from leaves (assertion); it’s an additional characteristic of phloem’s transport capabilities.

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11. Question

Assertion (A): Plants use an additional strategy besides root pressure to move water upwards to the highest points of tall plant bodies.

Reason (R): This additional strategy is primarily effective at night when stomata are typically closed, maximizing the impact of root pressure.

Answer: (c) Explanation: The assertion is true; plants use transpiration pull as an additional strategy beyond root pressure for upward water movement, especially in tall plants. The reason is false; this additional strategy (transpiration pull) is dominant during the day when stomata are open, not at night when stomata are typically closed.

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12. Question

Assertion (A): Xylem tissue primarily consists of sieve tubes and companion cells for the conduction of water.

Reason (R): At the roots, cells in contact with the soil actively take up ions, causing water to move into the root from the soil. Answer: (d)

Explanation: The assertion is false. Sieve tubes and companion cells are components of phloem tissue, involved in food transport. Xylem consists of vessels and tracheids for water conduction. The reason is true; root cells actively take up ions, which creates a concentration difference that draws water into the root from the soil.

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13. Question

Assertion (A): A proper transportation system is crucial for plants with large distances between their soil-contacting organs and chlorophyll-containing organs.

Reason (R): In such plants, diffusion processes alone would be inadequate to supply raw materials to leaves and energy stores to roots.

Answer: (a) Explanation: Both the assertion and the reason are true. The necessity of a dedicated transport system in large plants is directly explained by the inadequacy of diffusion to transport materials effectively over long distances within complex plant body designs.

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14. Question

Assertion (A): The translocation of food and other substances in phloem occurs in both upward and downward directions.

Reason (R): Phloem transports materials to diverse destinations including storage organs like roots, fruits, and seeds, as well as to growing organs.

Answer: (b) Explanation: Both the assertion and the reason are true. Phloem does transport in both directions, and it delivers to a variety of storage and growing organs. However, the specific destinations (reason) are examples of where materials go due to bidirectional flow, not the direct explanation for why phloem transport can occur in both directions (which is linked to pressure gradients and plant needs, generated by energy utilization).

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15. Question

Assertion (A): Transpiration helps in the absorption and upward movement of water and minerals dissolved in it from roots to the leaves.

Reason (R): Transpiration primarily increases root pressure, which then pushes the water column upwards.

Answer: (c) Explanation: The assertion is true; transpiration assists in the absorption and upward movement of water and minerals. The reason is false; transpiration creates a suction pull (transpiration pull), which is a pulling force, rather than increasing root pressure, which is a pushing force.

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16. Question

Assertion (A): The energy for translocation in phloem is directly generated by photosynthesis within the sieve tubes.

Reason (R): Materials like sucrose are transferred into phloem tissue using energy from ATP, which leads to an increase in osmotic pressure.

Answer: (d) Explanation: The assertion is false. While phloem transports products of photosynthesis, the energy for the translocation process itself comes from ATP, not directly from photosynthesis within the sieve tubes. The reason is true; ATP is used to load sucrose into the phloem, which in turn increases the osmotic pressure.

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17. Question

Assertion (A): In the spring, sugar stored in root or stem tissue can be transported to developing buds.

Reason (R): The phloem system facilitates the movement of material based on the plant’s needs, supplying energy to areas of active growth like buds.

Answer: (a) Explanation: Both the assertion and the reason are true. The example of sugar being transported from storage to buds in spring is explicitly used to illustrate how the phloem system is adaptable and moves materials according to the plant’s physiological demands. The reason directly explains the assertion.

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18. Question

Assertion (A): Xylem vessels and tracheids are interconnected, forming a continuous system for water conduction.

Reason (R): Water, after moving into the root xylem due to ion uptake, forms a column that is steadily pushed upwards by root pressure.

Answer: (b) Explanation: Both the assertion and the reason are true. Xylem components do form a continuous system for water transport. It is also true that root pressure creates an upward-pushed water column in the root xylem. However, the creation of an upward column by root pressure (reason) does not explain the structural interconnectedness of the xylem components (assertion). They are both facts about xylem function but not causally related as explanation/asserted.

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19. Questio

Assertion (A): The effect of root pressure in water transport is more important during the night.

Reason (R): During the day, stomata are typically closed, which significantly diminishes transpiration pull, making root pressure the primary force.

Answer: (c) Explanation: The assertion is true; root pressure’s contribution to water transport is indeed more significant at night. The reason is false; during the day, stomata are generally open, and transpiration pull is the major driving force, not root pressure.

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20. Question

Assertion (A): The movement of material in the phloem is directly driven by the active pumping of water molecules into the sieve tubes.

Reason (R): The translocation of food and other substances in phloem occurs in sieve tubes with the help of adjacent companion cells.

Answer: (d) Explanation: The assertion is false. Translocation in phloem is achieved by utilizing energy (ATP) to transfer substances like sucrose into the phloem tissue, which then increases osmotic pressure and causes water to move into it, rather than active pumping of water directly. The reason is true; translocation does take place in sieve tubes with the help of companion cells.

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21. Question

Assertion (A): Transpiration plays a critical role in both the absorption and upward movement of water and dissolved minerals from roots to the leaves.

Reason (R): The suction created by the evaporation of water from leaf cells pulls water from the xylem cells of roots, thereby facilitating both absorption and upward transport.

Answer: (a) Explanation: Both the assertion and the reason are true. Transpiration indeed assists in the absorption and upward movement of water and minerals. The reason accurately explains the mechanism (transpiration pull) by which this occurs, where the suction pulls water from the root xylem, linking it directly to both absorption and upward movement.

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22. Question

Assertion (A): Plants have low energy needs primarily because they do not move from one place to another.

Reason (R): Plant bodies contain a large proportion of dead cells in many tissues.

Answer: (b) Explanation: Both the assertion and the reason are true. Plants’ immobility contributes to their low energy needs (assertion). It is also true that a large proportion of plant body tissues consists of dead cells (reason). While both factors contribute to the low energy needs of plants, the reason (presence of dead cells) is an additional contributing factor, not the direct explanation for why immobility causes low energy needs.

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23. Question

Assertion (A): Root pressure is a more significant mechanism for water transport in plants during the nighttime.

Reason (R): During the day, stomata are generally closed, which significantly reduces the effect of transpiration pull, making root pressure more prominent.

Answer: (c) Explanation: The assertion is true; the effect of root pressure in water transport is more important at night. The reason is false; during the day, stomata are typically open, and transpiration pull is the major driving force for water movement, not root pressure.

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24. Question

Assertion (A): Phloem transports products of photosynthesis exclusively to the growing tips of stems and leaves.

Reason (R): Phloem delivers substances to various storage organs such as roots, fruits, and seeds, in addition to growing organs.

Answer: (d) Explanation: The assertion is false. Phloem transports photosynthetic products to a wide range of destinations, including storage organs (roots, fruits, seeds) and various growing organs, not exclusively to stem and leaf tips. The reason is true, accurately listing the diverse destinations for phloem-transported materials.

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25. Question

Assertion (A): The steady movement of water into root xylem creates a column of water that is steadily pushed upwards.

Reason (R): This initial movement of water into the root from the soil is a direct consequence of active ion uptake by root cells, creating a concentration difference.

Answer: (a) Explanation: Both the assertion and the reason are true. The active uptake of ions by root cells creates a concentration gradient, which causes water to move into the root (osmosis), thereby creating an upward-pushed water column in the root xylem. The reason directly explains the underlying cause of the water column formation.

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Human Excretion 

Assertion and Reason Questions on Human Excretion

Instructions: In the following questions, a statement of Assertion (A) is followed by a statement of Reason (R). Choose the correct option:

• (A) Both A and R are true, and R is the correct explanation of A.
• (B) Both A and R are true, but R is NOT the correct explanation of A.
• (C) A is true, but R is false.
• (D) A is false, but R is true.

Excretion In Plants 

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Instructions for Assertion (A) and Reason (R) Questions: Choose the most appropriate option:

• A) Both A and R are true and R is the correct explanation of A.
• B) Both A and R are true but R is not the correct explanation of A.
• C) A is true but R is false.
• D) A is false but R is true.

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Question 1

Assertion (A): Plant excretion mechanisms are fundamentally distinct from those employed by animals.

Reason (R): Plants utilize strategies like storing waste in dead cells and shedding parts, which are not typical animal excretory methods.

Question 2

Assertion (A): Oxygen is categorized as a waste product generated during photosynthesis.

Reason (R): Plants also have mechanisms to deal with carbon dioxide.

Question 3

Assertion (A): Plants efficiently remove excess water through the process of transpiration.

Reason (R): Transpiration primarily involves the absorption of water vapor from the atmosphere by leaves.

Question 4

Assertion (A): The majority of plant tissues are composed of dead cells that actively photosynthesize.

Reason (R): Plant waste products can be stored in cellular vacuoles.

Question 5

Assertion (A): The shedding of plant parts, such as leaves, serves as an excretory strategy.

Reason (R): Waste products accumulated by the plant can be stored within these parts before they are lost.

Question 6

Assertion (A): Cellular vacuoles are critical organelles for waste storage in plant cells.

Reason (R): Plants also store waste products as resins and gums in old xylem.

Question 7

Assertion (A): Plants store resins and gums specifically in old xylem.

Reason (R): Resins and gums are actively used by the plant for photosynthesis in the old xylem.

Question 8

Assertion (A): Plants only excrete waste products through the shedding of leaves.

Reason (R): Plants can excrete some waste substances directly into the soil around them.

Question 9

Assertion (A): The unique waste management strategies of plants are partly due to their tissue composition.

Reason (R): Plants can utilize their dead cells and the ability to lose parts for waste disposal.

Question 10

Assertion (A): Plants have mechanisms to handle both oxygen and carbon dioxide.

Reason (R): Oxygen itself can be thought of as a waste product generated during photosynthesis.

Question 11

Assertion (A): Many plant waste products are stored permanently in cellular vacuoles.

Reason (R): Cellular vacuoles are primarily involved in the transport of water through the xylem.

Question 12

Assertion (A): Transpiration is the primary method plants use to absorb nutrients from the soil.

Reason (R): Plants can get rid of excess water by transpiration.

Question 13

Assertion (A): Resins and gums are significant forms of stored waste products in plants.

Reason (R): These substances are specifically found accumulated in older, less active xylem tissues.

Question 14

Assertion (A): Plants employ various strategies for waste management, unlike animals.

Reason (R): Plants also deal with the management of CO2 levels.

Question 15

Assertion (A): The ability to lose parts like leaves is a unique waste disposal strategy for plants.

Reason (R): This strategy is exclusively used for the removal of toxic heavy metals.

Question 16

Assertion (A): Plants excrete all their waste products directly into the soil.

Reason (R): Waste products can be stored within a plant’s cellular vacuoles.

Question 17

Assertion (A): The storage of waste products in dead cells is an effective strategy for plants.

Reason (R): By utilizing dead tissues, plants can isolate waste substances, preventing their interference with active metabolic processes.

Question 18

Assertion (A): Plants have mechanisms to handle excess oxygen within their systems.

Reason (R): Oxygen itself can be thought of as a waste product generated during photosynthesis.

Question 19

Assertion (A): Transpiration helps plants to manage their water balance.

Reason (R): Transpiration causes water to be absorbed from the roots into the leaves.

Question 20

Assertion (A): All waste products generated by plants are stored permanently within their internal structures.

Reason (R): Some plant waste substances are excreted into the surrounding soil.

Question 21

Assertion (A): Plant strategies for waste management are diverse and multi-faceted.

Reason (R): They involve internal storage, shedding of parts, and external release into the soil.

Question 22

Assertion (A): Waste products stored in cellular vacuoles are isolated from the active cytoplasm.

Reason (R): Resins and gums are another form of waste storage found in old xylem.

Question 23

Assertion (A): Plants have unique methods for dealing with excess CO2.

Reason (R): Plants typically excrete carbon dioxide by releasing it into the water around their roots.

Question 24

Assertion (A): All plants store resins and gums exclusively in their actively photosynthesizing leaves.

Reason (R): Resins and gums are specifically stored as waste products in old xylem.

Question 25

Assertion (A): The ability of plants to lose parts like leaves contributes significantly to their overall waste management strategy.

Reason (R): This allows for the physical removal of accumulated waste products that have been stored in those parts.

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