Fact 1: All chemical reactions require activation energy to get started.

Fact 2: Chemical changes are referred to as a chemical reaction.

Given the two facts above, answer the question "What require activation energy to get started?" with the following options: 
- changing colors
 - chemical additions
 - reacting colors
 - Firecrackers
 - an engine
 - heating liquids
 - Organic compounds
 - chemical changes


 

        chemical changes 