Fact 1: Water vapor cooling causes that water vapor to condense.

Fact 2: Clouds form by the condensation of water vapor.

Given the two facts above, answer the question "what are clouds formed from?" with the following options: 
- water vapor
 - oxygen
 - Heat energy
 - heating liquids
 - evaporation
 - carbon dioxide
 - air
 - boiling


 

 water vapor        