You are presented with the question "What controls anti-aging?" and the following answer choices: 
- A computer
 - air
 - chemical messengers
 - ice
 - an electric stove
 - Electrical energy
 - water
 - Chemical energy

Now knowing that hormones are chemical messengers that control many body functions and growth hormone is in many ways an anti-aging hormone, choose the best answer.


 

   chemical messengers      