Which of the following is true about gastric acid?

• A. Neutralizes digestive enzymes
• B. Breaks down carbohydrates in the mouth
• C. Aids in emulsifying fats
• D. Kills bacteria in the stomach

Answer: (D)

Gastric acid creates a highly acidic environment in the stomach, mainly due to hydrochloric acid. This low pH acts as a protective barrier by killing many microorganisms that come with food, which is why it’s true that gastric acid kills bacteria in the stomach. It also activates pepsinogen to pepsin and helps denature proteins, aiding protein digestion. It does not neutralize digestive enzymes—that happens later in the small intestine with bicarbonate—and it doesn’t break down carbohydrates in the mouth or emulsify fats, which are handled by salivary amylase in the mouth and bile/pancreatic lipase in the small intestine.