to become better hunters. in order to re-populate the Earth. in response to an altering environment. to become useful for humans.
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: According to the fossil record, the first horses were smaller than modern species. Throughout time, horses have gradually changed
Possibilities:
- to become better hunters.
- in order to re-populate the Earth.
- in response to an altering environment.
- to become useful for humans.

in response to an altering environment.