Fact 1: Energy is used for heating a building by a heating system.

Fact 2: Sometimes, in a cold climate it is necessary to use heat, but use only slow heat.

Given the two facts above, answer the question "What do humans use when living in a cold climate?" with the following options: 
- energy
 - spaceships
 - hair
 - freezers
 - weapons
 - fur
 - Blankets
 - chemicals


 

 energy        