Fact 1: Heating salt water causes the water to evaporate while the salt remains.

Fact 2: When water evaporates, salts in the water remain and become more concentrated.

Given the two facts above, answer the question "What increases in concentration when water evaporates?" with the following options: 
- nektar
 - sugar
 - sweat
 - salt
 - potash
 - Gases
 - maples
 - energy


 

    salt     