Which of the following processes does the body not use protein to perform?
a. repairing muscles
b. producing hormones
c. making hemoglobin
d. creating amino acids

The best answer is D.

Man obtains most of his amino acids from diet, and mostly the essential amino acids. Of the basic set of 20 amino acids, man can only make 9,  but these are considered non-essential anyway. They are made from non-protein raw materials such as pyruvate.

Amino acids themselves are the building blocks for proteins.

Protein is the raw material for muscle growth and repair.

Hormones are made from protein and  cholesterol.

Hemoglobin molecule is made up of four protein chains with a heme group attached to each .

However in all these processes, enzymes which are protein in nature are employed but it is only creation of amino acids that does not need protein as a raw material.