Question

which substance in the stomach breaks down the proteins?
a. bile
b. gastric acid
c. peptide
d. pepsin
e. saliva

Explanation:

• Bile is produced by the liver and aids in fat digestion, not protein breakdown.
• Gastric acid (hydrochloric acid) creates an acidic environment in the stomach but does not directly break down proteins.
• Peptide is a short chain of amino acids, not a substance that breaks down proteins.
• Pepsin is an enzyme in the stomach that specifically breaks down proteins into smaller peptides.
• Saliva is in the mouth and contains amylase for carbohydrate digestion, not relevant to stomach protein breakdown.

Answer:

D. pepsin