You are presented with the question "What require activation energy to get started?" and the following answer choices: 
- changing colors
 - chemical additions
 - reacting colors
 - Firecrackers
 - an engine
 - heating liquids
 - Organic compounds
 - chemical changes

Now knowing that all chemical reactions require activation energy to get started and chemical changes are referred to as a chemical reaction, choose the best answer.


 

        chemical changes 