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

Ex Input:
The brain and spinal cord are part of what system, which serves as a control center?

Ex Output:
central nervous system

Ex Input:
What can be used to determine the mass of a quantity of material?

Ex Output:
molar masses

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