Fact 1: Cooking food requires adding heat energy.

Fact 2: Many of foods that humans eat are cooked, recooked, and then warmed up.

Given the two facts above, answer the question "What do humans add to their food?" with the following options: 
- nutrients
 - Proteins
 - Greenhouse gases
 - pain
 - gasoline
 - Heat energy
 - Energy.
 - coal


 

      Heat energy   