LIFE SCIENCE

Detailed explanation-1: -mutation and genetic drift. Option (b) is correct as mutation and gene flow evolutionary forces can introduce new genetic variation into a population.

Detailed explanation-2: -Another form of natural selection is positive selection, also called Darwinian selection, in which natural selection favors genetic mutations that are advantageous for the fitness or the survival of individuals. Positive selection will increase the frequencies of such variants in the population gene pool [25, 40].

Detailed explanation-3: -Mutations to an individual’s DNA may introduce new variation into a population.

Detailed explanation-4: -Natural selection can produce genetic variation among demes within a metapopulation if different selective pressures prevail in different demes. If Ne is large enough to discount the effects of genetic drift, then we expect directional selection to fix the favored allele within a given focal deme.