How does animal behavior relate to natural selection

Animals react to how they feel certain things. If they don’t feel comfortable around them because they aren’t suited to their surroundings, they will feel alert and scared. For example: a green snake can hide in trees and blend in. But if that snake isn’t with a suited area, he will most likely get attacked, because he can’t blend in.

So natural selection plays a big part on how animals react or behave because animals may or may not be suited to their surroundings.