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

Ex Input:
Liquids that mix with each other in all proportions are said to be miscible, maning they have infinite mutual what?

Ex Output:
solubility

Ex Input:
What is the name of the process where light is produced without heat?

Ex Output:
luminescence

Ex Input:
Many of the hormones are secreted in response to what signals of the body?

Ex Output:
nervous system signals