What function does the low pH of the stomach serve in the digestive system?

• A. It facilitates the absorption of nutrients in the small intestine.
• B. It activates pepsinogen into pepsin for protein digestion.
• C. It neutralizes the acidic chyme from the stomach.
• D. It protects the stomach lining from mechanical damage.

Answer: (B)

Verified step by step guidance

1. Understand the role of stomach acid: The stomach secretes hydrochloric acid (HCl), which creates a low pH environment.
2. Recognize the importance of enzyme activation: Pepsinogen, an inactive enzyme precursor, is converted into pepsin in the presence of low pH, which is crucial for protein digestion.
3. Consider the digestive process: Pepsin breaks down proteins into smaller peptides, facilitating further digestion and absorption in the small intestine.
4. Evaluate the options: The low pH does not directly facilitate nutrient absorption in the small intestine, neutralize chyme, or protect the stomach lining from mechanical damage.
5. Conclude the primary function: The low pH of the stomach primarily serves to activate pepsinogen into pepsin, enabling effective protein digestion.