Fact 1: Heating an egg causes a chemical reaction in the egg.

Fact 2: High heat causes the protein in eggs to become tough and rubbery.

Given the two facts above, answer the question "What in an egg causes protein to become rough and rubbery?" with the following options: 
- layers of fat
 - stamina
 - coded genes
 - lining
 - Converted sugar
 - chemical reaction
 - shell
 - Chemical energy


 

      chemical reaction   