Fact 1: Water vapor condensing in clouds causes rain.

Fact 2: Heavy rain or thunder storms usually cause flash floods.

Given the two facts above, answer the question "Water vapor condensing in clouds usually cause what?" with the following options: 
- Pollution
 - Heat energy
 - kinetic energy
 - harmful substances
 - flash floods
 - Greenhouse gases
 - Evaporation
 - Greenhouse gasses


 

     flash floods    