Question

what is the main effect of overpopulation on animals?
more animals are used for food.
extinction occurs due to loss of habitat.
a change in the animal population harms the environment.
social conflict occurs due to limited resources.

Explanation:

Overpopulation often leads to habitat - destruction as humans expand their living and agricultural areas. This loss of habitat is a major cause of animal extinction. While other options may be consequences in some cases, habitat loss and resulting extinction are the most significant effects on animals due to overpopulation.

Answer:

Extinction occurs due to loss of habitat.