Fact 1: Burning wood is used to produce heat.

Fact 2: Heat is added and the temperature of the water increases.

Given the two facts above, answer the question "What is used to increase temperature?" with the following options: 
- activation energy
 - ice
 - electricity
 - snow
 - glaciers
 - burning wood
 - Electrical energy
 - Fuel cells


 

      burning wood   