by protecting deer from other predators by controlling the deer population by decreasing diversity within the herd by protecting the deer from disease
I gave my students this multiple choice question: Deer provide food for wolves. How does this relationship also benefit the deer herd?

Only one answer is correct among these 4 choices:
- by protecting deer from other predators
- by controlling the deer population
- by decreasing diversity within the herd
- by protecting the deer from disease

Could you tell me which one is correct?

by controlling the deer population