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

Fact 2: Perspiration There are about 2 million sweat glands in the average human body.

Given the two facts above, answer the question "What wets the skin, and when it evaporates, it cools the body?" with the following options: 
- heat energy
 - acetic acid
 - Air conditioner
 - salt and water.
 - Skin oil
 - water vapor
 - Perspiration
 - A towel


 

       Perspiration  