the amount of snow in the area each year the number of birds that live in the area the number of trees in the area the amount of food available in the area
I gave my students this multiple choice question: Which best determines the number of wolves that can live in an area?

Only one answer is correct among these 4 choices:
- the amount of snow in the area each year
- the number of birds that live in the area
- the number of trees in the area
- the amount of food available in the area

Could you tell me which one is correct?

the amount of food available in the area