Given a scientific question, generate a correct answer to it.

Ex Input:
Sometimes two or more distinct phenotypes can each have their advantages and be selected for by natural selection; this is known as what?

Ex Output:
diversifying selection

Ex Input:
What works by providing a lower energy pathway from reactants to products?

Ex Output:
catalyst

Ex Input:
Insulin and glucagon help keep blood glucose levels in the normal range because of what type of effects?

Ex Output:
antagonistic