Assertion(A): In C4 plants, photorespiration does not occur.
Reason(R): They have a mechanism that increases the concentration of CO2 at the enzyme site.
Choices for Assertions and reasons:
1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true, but (R) is not the correct explanation of (A).
3. (A) is true, but (R) is false.
4. (A) is false, but (R) is true.

Subtopic:  Question on C4 Pathway |
 91%
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Assertion(A): As a plant photosynthesises, many factors will simultaneously affect its rate.
Reason(R): Usually one factor is the major cause or is the one that limits the rate.
Choices for Assertions and reasons:
1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true, but (R) is not the correct explanation of (A).
3. (A) is true, but (R) is false.
4. (A) is false, but (R) is true.
Subtopic:  Factors Affecting Photosynthesis |
 62%
From NCERT
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Assertion(A): When several factors affect any [bio] chemical process, Blackman’s (1905) Law of Limiting Factors comes into effect.
Reason(R): At any point of photosynthesis, the rate will be determined by the factor available at sub-optimal levels.
Choices for Assertions and reasons:
1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true, but (R) is not the correct explanation of (A).
3. (A) is true, but (R) is false.
4. (A) is false, but (R) is true.
Subtopic:  Factors Affecting Photosynthesis |
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Assertion(A): The effect of water as a factor is more through its effect on the plant, rather than directly on photosynthesis.
Reason(R): Water stress also makes leaves wilt and increases metabolic activity as well.
Choices for Assertions and reasons:
1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true, but (R) is not the correct explanation of (A).
3. (A) is true, but (R) is false.
4. (A) is false, but (R) is true.
Subtopic:  Factors Affecting Photosynthesis |
 60%
From NCERT
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Assertion(A): It is only the green part of the plants that release oxygen.
Reason(R): Ingenhousz showed that in bright sunlight, small bubbles were formed around the green parts.
Choices for Assertions and reasons:
1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true, but (R) is not the correct explanation of (A).
3. (A) is true, but (R) is false.
4. (A) is false, but (R) is true.
Subtopic:  Historical View: Experiments |
From NCERT
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Assertion(A): The proton gradient across the thylakoid membrane is very important for photosynthesis.
Reason(R): The breakdown of this gradient leads to the synthesis of ATP.
Choices for Assertions and reasons:
1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true, but (R) is not the correct explanation of (A).
3. (A) is true, but (R) is false.
4. (A) is false, but (R) is true.
Subtopic:  Dark Reaction : Calvin Cycle |
 86%
From NCERT
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Assertion(A): For every CO2 molecule in the Calvin cycle, 3 molecules of ATP and 2 of NADPH are required.
Reason(R): It is probably to meet this difference in the number of ATP and NADPH used in the dark reaction that the cyclic phosphorylation takes place.
Choices for Assertions and reasons:
1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true, but (R) is not the correct explanation of (A).
3. (A) is true, but (R) is false.
4. (A) is false, but (R) is true.
Subtopic:  Dark Reaction : Calvin Cycle |
From NCERT
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Assertion(A): Except for plants in shade or in dense forests, light is rarely a limiting factor in nature.
Reason(R): Plants show light saturation at 10 percent of the full sunlight.
Choices for Assertions and reasons:
1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true, but (R) is not the correct explanation of (A).
3. (A) is true, but (R) is false.
4. (A) is false, but (R) is true.
Subtopic:  Factors Affecting Photosynthesis |
 70%
From NCERT
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Assertion(A): Green plants are called autotrophs.
Reason(R): The green plants synthesise the food they need through photosynthesis.
1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true, but (R) is not the correct explanation of (A).
3. (A) is true, but (R) is false.
4. (A) is false, but (R) is true.
Subtopic:  Factors Affecting Photosynthesis |
 94%
From NCERT
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Assertion(A): Oxygen evolved from green plants actually comes from the water molecule.
Reason(R): This was proved using radioisotope techniques.
1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true, but (R) is not the correct explanation of (A).
3. (A) is true, but (R) is false.
4. (A) is false, but (R) is true.
Subtopic:  Historical View: Experiments |
From NCERT
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