Curdling of milk in the stomach is due to the action of -

Options

A. Pepsin
B. Rennin
C. Ptyalin
D. Enterokinase

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks which substance is responsible for the curdling of milk in the stomach.

2. **Identifying the Options**: The options provided are:
- Papsin
- Renin
- Tialin
- Enterokinase

3. **Analyzing Each Option**:
- **Papsin**: This is not a recognized enzyme related to milk curdling.
- **Renin**: This is a proteolytic enzyme produced by the chief cells in the stomach and is known to curdle milk.
- **Tialin**: This enzyme is involved in the digestion of carbohydrates, not milk.
- **Enterokinase**: This enzyme activates trypsinogen to trypsin but does not play a role in curdling milk.

4. **Conclusion**: The enzyme responsible for curdling milk in the stomach is **Renin**. It helps convert liquid milk into a semi-solid form, which is essential for proper digestion, especially in young animals.

5. **Final Answer**: The correct option is **Renin**.