Question

what is the role of prey animals in an ecosystem?
to reduce the number of predators by spreading disease
to help get rid of pests such as ecosystem engineers
to help ecosystem engineers make changes to their habitat
to provide food for the predators that hunt them

Explanation:

Prey animals are a food source for predators in an ecosystem. They do not primarily reduce predator numbers by spreading disease, nor are they related to getting rid of or helping ecosystem - engineers in the ways described in the other options.

Answer:

D. to provide food for the predators that hunt them