According to Darwin the organic evolution is due to intraspecific competition. Individuals of same species have variation in characteristics. Those characteristics which enable some to survive better in natural conditions (climate, food, physical factors etc.) would outbreed others that are less-endowed to survive under such natural conditions. There, therefore, will survive more and hence are selected by nature. He called it natural selection and implied it as a mechanism of evolution.

Correct Option: D

According to Darwin the organic evolution is due to intraspecific competition. Individuals of same species have variation in characteristics. Those characteristics which enable some to survive better in natural conditions (climate, food, physical factors etc.) would outbreed others that are less-endowed to survive under such natural conditions. There, therefore, will survive more and hence are selected by nature. He called it natural selection and implied it as a mechanism of evolution.

Genetic drift is variation in gene frequencies within populations can occur by chance rather than by natural selection, sometimes the change in allele frequency is so different in the new sample of population that they become a different species. The original drifted population becomes founders and the effect is called founder effect.

Correct Option: A

Genetic drift is variation in gene frequencies within populations can occur by chance rather than by natural selection, sometimes the change in allele frequency is so different in the new sample of population that they become a different species. The original drifted population becomes founders and the effect is called founder effect.

Wings of a bird and flippers of a whale are modified forelimbs.

Correct Option: D

Wings of a bird and flippers of a whale are modified forelimbs.

Both statements are correct because primitive atmosphere was reducing and chlorophyll appeared later on. Chemoautotrophs were the first autotrophic organisms unable to perform photolysis of water and never released oxygen.

Correct Option: C

Both statements are correct because primitive atmosphere was reducing and chlorophyll appeared later on. Chemoautotrophs were the first autotrophic organisms unable to perform photolysis of water and never released oxygen.

Analogous structures are those that have the same function, but they are not derived from a common ancestor and have undergone different patterns of development i.e., Convergent evolution which is natural selection that favors the same type of structure in different ancestors.

Correct Option: B

Analogous structures are those that have the same function, but they are not derived from a common ancestor and have undergone different patterns of development i.e., Convergent evolution which is natural selection that favors the same type of structure in different ancestors.