Heating an egg causes a chemical reaction in the egg.
High heat causes the protein in eggs to become tough and rubbery.
A chemical reaction in an egg causes protein to become rough and rubbery.
What in an egg causes protein to become rough and rubbery?

[A] layers of fat
[B] stamina
[C] coded genes
[D] lining
[E] Converted sugar
[F] chemical reaction
[G] shell
[H] Chemical energy