Digestion of protein completed in which part?

Protein digestion begins in the stomach with pepsin, but its completion primarily occurs in the small intestine. Specifically, the duodenum, the first section of the small intestine, is where the bulk of protein digestion is completed. Here, pancreatic enzymes like trypsin and chymotrypsin, along with brush border enzymes, break down polypeptides into smaller peptides and amino acids, which are then absorbed.

• Option B, "Stomach," initiates protein digestion but does not complete it.
• Options C, "Jejunum," and D, "Ileum," are subsequent parts of the small intestine where absorption of nutrients, including amino acids, predominantly takes place, but the major enzymatic breakdown of proteins into absorbable units is largely finished in the duodenum.