Fact 1: Condensation is when change from a gas into a liquid by reducing heat energy.

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

Given the two facts above, answer the question "Water vapor is formed when gas changes into a liquid by reducing what?" with the following options: 
- direct energy
 - electrical energy
 - kinetic energy
 - heat energy
 - solar flares
 - Temperature
 - energy
 - water power


 

    heat energy     