Assertion(A): Gene flow increases genetic variations.
Reason(R): Random introduction of new alleles into recipient population and their removal from donor population affect allele frequency.
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. Both (A) and (R) are false.

Subtopic:  Hardy Weinberg Law: 1 | Hardy Weinberg Law: 2 | Hardy Weinberg Law |
 65%
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Assertion(A): Among primates, chimpanzee is closest relative to the present day humans.
Reason(R): The banding pattern of autosomes 3 and 6 of humans and chimapanzee is remarkably similar.
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. Both (A) and (R) are false.
Subtopic:  Introduction to Human Evolution | Classification of Primates | Evolution Prior to Ape Man: 1 | Evolution Prior to Ape Man: 2 | Evolution of Homo Sapiens |
 80%
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Assertion(A): From evolutionary point of view, human gestation period is believed to be shortening.
Reason(R): One major evolutionary trend in humans has been the larger head undergoing relatively faster growth in the foetal stage.
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. Both (A) and (R) are false.
Subtopic:  Introduction to Human Evolution | Classification of Primates | Evolution of Homo Sapiens |
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Assertion(A): Fitness is the end result of ability to adapt and get selected by nature.
Reason(R): Some organisms are better adapted to survive in an otherwise hostile environment.
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. Both (A) and (R) are false.
Subtopic:  Darwin's Theory | Summary of Darwin's Theory | Drawbacks of Darwin's Theory |
 53%
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Assertion(A): According to Lamarck the rate and survival of organisms are different due to variations.
Reason(R): Lamarck gave the theory of pangenesis.
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. Both (A) and (R) are false.
Subtopic:  Theory of Evolution & Lamarckism |
 67%
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Assertion(A): Sickle cell anaemia in malaria endemic area is an example of directional selection.
Reason(R): Individuals for sickle cell anaemia have defective gene in X chromosomes.
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. Both (A) and (R) are false.
Subtopic:  Darwin's Theory | Genetic Basis of Adaptation |
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Assertion(A): Australian marsupials can be taken as an example of adaptive radiation.
Reason(R): A number of marsupials, evolved from an ancestral stock, but all within the Australian island continent.
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. Both (A) and (R) are false.
Subtopic:  Theory of Evolution & Lamarckism | Modern Theory of Evolution | Genetic Basis of Adaptation |
 76%
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Assertion(A): Analogous structures are a result of convergent evolution.
Reason(R): Different structures evolving for the same function and hence having similarity.
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. Both (A) and (R) are false.
Subtopic:  Concept of Organic Evolution: Evidence: 1 | Concept of Organic Evolution: Evidence: 2 | Concept of Organic Evolution: Evidence: 3 | Modern Theory of Evolution |
 90%
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Assertion(A): Evolution is not occurring at all at present.
Reason(R): Evolution takes a very short time.
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. Both (A) and (R) are false.
Subtopic:  Other Theories of Origin of Life |  A BRIEF ACCOUNT OF EVOLUTION |
 82%
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Assertion(A): Evolution is not a directed process in the sense of determination.
Reason(R): It is stochastic process based on chance events in nature and chance mutation in the organisms.
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. Both (A) and (R) are false.
Subtopic:  Theory of Evolution & Lamarckism | Modern Theory of Evolution | Natural Selection | Genetic Basis of Adaptation |
 77%
From NCERT
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