You are presented with the question "What do ALL chemical changes require to occur?" and the following answer choices: 
- during the day
 - heating liquids
 - Activation energy
 - wavelengths and photons
 - Burning fuel and air
 - kinetic energy
 - electromagnetic energy
 - direct energy

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


 

   Activation energy      