Fact 1: Sweat wets the skin, and when it evaporates, it cools the body.

Fact 2: Sweat is water, salt, some urea.

Given the two facts above, answer the question "The thing that cools the body contains what?" with the following options: 
- liquid
 - matter
 - vapors
 - oxygen
 - Urea
 - nektar
 - water
 - Air


 

     Urea    