Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
--------
Question: Chemical digestion mainly occurs in the small intestine.

Answer: Where does chemical digestion mainly occur?


Question: Are humans a new or old species on the earth?

Answer: Are humans a new or old species on the earth?


Question: Protein is an important part of a healthy diet because it is needed to repair tissue.

Answer:
Why is protein an important part of a healthy diet?