A new pesticide has been introduced to the habitat of this population of beetles.

Which describes the effect of this environmental change?

A) decreased genetic variation

B) increased genetic variation

C) genetic drift

D) gene flow

The correct option is A.

Decrease in genetic variation occurs when a large number of members of a particular population are prevented from reproducing, thus leading to a significant reduction in the size of the population. In the question given above, pesticide was introduced in order to kill off the beetles, this will cause a decrease in the genetic variation of the population of beetles.