Which of the following is necessary for natural selection to act on a population of organisms? a) genetic variation among members of the population b) unlimited resource availability to members of the population c) asexual reproduction by members of the population d) exponential growth of the population

The correct answer is A) Genetic variation among members of the population

Explanation:

In natural selection, specific traits provide a survival advantage to some individuals in a population, and this causes these individuals to survive and reproduce successfully, while those that lack the trait or traits will disappear. Moreover, this phenomenon causes the evolution of a population as dominant traits change due to the selection of those that are more suitable to survive.

All of this can be possible only if there is genetic variation in the population because it is this variation the one that causes there are traits that can make some individuals more likely to survive than others. On the opposite, if the population is genetically homogeneous, for example, in populations that reproduce asexually, it is more likely the population disappears as there are no different traits that can provide an advantage to some individuals, and determine a change through natural selection. Thus, for natural selection to occur there should be genetic variation (Option A).