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

Fact 2: Flash evaporators are used to make fresh water from salt water.

Given the two facts above, answer the question "Doing what to salt water causes the water to become fresh water?" with the following options: 
- watershred
 - freezing
 - Regrows it
 - migrate
 - pouring
 - heating
 - cooling
 - erosion


 

      heating   