You are presented with the question "what travels throughout the body in the blood?" and the following answer choices: 
- chemical messengers
 - carbon monoxide
 - Veins and arteries.
 - bacterial messengers
 - density
 - kinetic energy
 - electromagnetic energy
 - matter vibrating

Now knowing that endocrine hormones travel throughout the body in the blood and hormones are the chemical messengers of the body's endocrine system, choose the best answer.


 

 chemical messengers        