You are presented with the question "The thing that cools the body contains what?" and the following answer choices: 
- liquid
 - matter
 - vapors
 - oxygen
 - Urea
 - nektar
 - water
 - Air

Now knowing that sweat wets the skin, and when it evaporates, it cools the body and sweat is water, salt, some urea, choose the best answer.


 

     Urea    