The acid present in the stomach

Options

A. kills the harmful bacteria that may enter along with the food.
B. protects the stomach lining from harmful substances.
C. digests starch into simpler sugars.
D. makes the medium alkaline.

Answer

**Step-by-Step Solution:**

1. **Identify the Acid in the Stomach**: The acid present in the stomach is hydrochloric acid (HCl).

2. **Understand the Role of Hydrochloric Acid**: Hydrochloric acid plays several important roles in the digestive process. It creates an acidic environment in the stomach which is essential for digestion.

3. **Evaluate the Options**:
- **Option A**: Kills harmful bacteria that may enter with food. This is a true function of HCl.
- **Option B**: Protects the stomach lining from harmful substances. This is incorrect; mucus protects the lining, not the acid.
- **Option C**: Digests starch into simple sugars. This is incorrect; starch digestion primarily occurs in the mouth and small intestine, not in the stomach.
- **Option D**: Makes the medium alkaline. This is incorrect; HCl makes the medium acidic.

4. **Select the Correct Answer**: Based on the evaluation, the correct answer is **Option A**: kills the harmful bacteria that may enter along with the food.

5. **Conclusion**: Hydrochloric acid is essential for digestion in the stomach, primarily for killing bacteria and providing an acidic environment for the action of digestive enzymes.

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