Concept:Protein digestion is completed in the small intestine after starting in the stomach.
Explanation:In the stomach, the enzyme pepsin begins the chemical digestion of proteins.
The acidic stomach environment helps break protein chains into smaller peptides.
These partially digested proteins then move into the small intestine.
Here, pancreatic enzymes such as trypsin and intestinal peptidases complete the digestion.
The final products are amino acids, which are absorbed in the small intestine.
Thus, protein digestion starts in the stomach and ends in the small intestine.
Answer:B. small intestine.