Question

atural selection decreases genetic variation in a population.\ this statement is: sometimes true always true never true

Explanation:

Natural selection can act in different ways. For example, in stabilizing selection, it favors intermediate phenotypes and reduces genetic variation. But in disruptive selection, it favors extreme phenotypes, which can maintain or even increase genetic variation in some aspects (by keeping multiple extreme traits in the population). So the statement isn't always true or never true.

Answer:

sometimes true