One similarity between natural selection and genetic drift is that both events
a. are based completely on chance
b. begin with one or more mutations
c. involve a change in a population's allele frequency
d. take place only in very small groups

Correct C). Involve a change in a population's allele frequency

Natural selection is the process in the traits that are favorable are more likely to reproduce and are able to pass these traits to their offspring. Genetic drift is defined as the change in the allele frequency of a population that is caused due to random changes in the population.

Both natural selection and genetic drift are the mechanisms of evolution, the main difference is that in genetic drift allele frequency changes by chance and in natural selection allele frequency change as a result of differential reproductive success.

Hence, the correct answer would be option C.

c. movement because i took the test and it lets me review my answers