Fact 1: Hormones control many cell activities, so they are very important for homeostasis.

Fact 2: Homeostasis is the central theme of physiology.

Given the two facts above, answer the question "what is hormones controlling cell activities important to?" with the following options: 
- gravity
 - it helps plants in growing
 - the sun
 - central theme of physiology
 - female sex cells
 - density
 - Generating heat
 - production of energy


 

    central theme of physiology     