Fact 1: Water vapor condensing in clouds causes rain.

Fact 2: Water vapor is a gas in the air.

Given the two facts above, answer the question "What condenses in clouds to cause rain?" with the following options: 
- evaporation
 - chlorofluorocarbons
 - Organic compounds
 - carbon dioxide
 - a gas in the air
 - Chemical energy
 - peachleaf willow
 - flooding


 

     a gas in the air    