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

Ex Input:
Herbivores are heterotrophs that eat only or mainly what?

Ex Output:
plants

Ex Input:
What is secreted before ejaculation to neutralize acidic urine remaining in the urethra?

Ex Output:
clear mucus

Ex Input:
Changes from a less-ordered state to a more-ordered state (such as a liquid to a solid) are always what?

Ex Output:
exothermic