Fact 1: Hormones are chemical messengers that control many body functions.

Fact 2: Growth hormone is in many ways an anti-aging hormone.

Given the two facts above, answer the question "What controls anti-aging?" with the following options: 
- A computer
 - air
 - chemical messengers
 - ice
 - an electric stove
 - Electrical energy
 - water
 - Chemical energy


 

   chemical messengers      