Suppose the environment changes. For example:

A. The rainfall decreases.

B. A competing species (goats) moves in that eats the same kind of grass.

C. Small coyotes arrive with a fondness for baby sheep.

Think of some small mutations that might help the sheep population survive in each of these new circumstances.

Your response Mutation A:
Why it might help:

Your response Mutation B:
Why it might help:

Your response Mutation C:
Why it might help: