Question

which scenario would represent a situation that reduces the effect of genetic drift?
the population is very large.
natural selection is not acting.
individuals are mating randomly.
no mutations exist in the population.
no gene flow exists between populations.

Explanation:

Genetic drift is the random change in allele frequencies in a population. It has a more significant impact in small populations. In a large population, random fluctuations in allele frequencies (which is what genetic drift is) are averaged out. So, a large population size reduces the effect of genetic drift. Natural selection not acting, random mating, no mutations, and no gene flow are conditions for Hardy - Weinberg equilibrium but do not directly reduce the effect of genetic drift.

Answer:

The population is very large.