Answer: D. creating amino acids
Amino acids are the building blocks of proteins. A typical amino acid structure consists of a central carbon atom covalently bonded to a carboxyl group, an amino group, and a hydrogen atom. When numerous amino acid structures combine, they form proteins. In order words, proteins are long chain amino acids. The body does not use proteins to create amino acids as proteins are amino acids themselves.
During digestion, proteins are broken down into amino acids and these amino acids are utilized by the body for a variety of functions. Some of these functions include the breaking down of food, for growth of organs as well as the entire body structure, for body tissue repair, and many other functions. The Hemoglobin is made of proteins and it helps in transporting oxygen in the blood. The hemoglobin is located in the red blood cell and about 96% of the dry content of the red blood cell is made up of proteins.