You are presented with the quiz "What cools the body?" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "sweat wets the skin, and when it evaporates, it cools the body" and "fig 4-23 sweat contains water, salt, lactic acid, vit". 

So, what's the best answer to the question?


 

      Evaporation of water     