Protein digestion starts in_____

Options

A. stomach
B. mouth
C. small intestine
D. oesophagus

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks where protein digestion begins in the human body.

2. **Identifying the Options**: The options provided are:
- Stomach
- Mouth
- Small intestine
- Esophagus

3. **Analyzing the Digestion Process**:
- **Mouth**: In the mouth, mechanical digestion occurs, where food is chewed, but chemical digestion of proteins does not start here.
- **Esophagus**: The esophagus is primarily a passageway for food to travel from the mouth to the stomach and does not play a role in protein digestion.
- **Stomach**: The stomach is where protein digestion begins. It contains proteolytic enzymes that chemically break down proteins into smaller peptides.
- **Small Intestine**: While protein digestion continues in the small intestine, the initial breakdown starts in the stomach.

4. **Conclusion**: Based on the analysis, protein digestion starts in the stomach.

**Final Answer**: Protein digestion starts in the stomach.

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