Fact 1: Protein is used to repair cells by the human body.

Fact 2: Pain in the body indicates there is a wound which requires cell repair and cell regeneration.

Given the two facts above, answer the question "what does wound healing require" with the following options: 
- protein
 - nutrients
 - Enzymes
 - food
 - blood
 - amino acids
 - carbohydrates
 - cells


 

 protein        