You are presented with the question "What happens when water vapors cool down?" and the following answer choices: 
- colder weather
 - Fog is formed
 - Heat energy
 - evaporation
 - chemical changes
 - Something to move
 - prolactin release
 - Energy.

Now knowing that fog is formed by water vapor condensing in the air and fog is essentially very low clouds, consisting of water vapor cooling and beginning to condense, choose the best answer.


 

  Fog is formed       