Which of the following regulate the exit of food from stomach into small intestine ?

Options

A. Valve
B. Sphincter muscle
C. Villi
D. All of these.

Answer

To answer the question "Which of the following regulates the exit of food from stomach into small intestine?", we will analyze the options provided and determine the correct answer step by step.

### Step-by-Step Solution:

1. **Understanding the Question**: The question is asking which structure regulates the movement of food from the stomach to the small intestine.

2. **Analyzing the Options**:
- **Option 1: Walls**: The walls of the stomach and intestine provide structure but do not specifically regulate the exit of food.
- **Option 2: Sphincter Muscles**: These are specialized muscles that control the opening and closing of passages in the body. The pyloric sphincter is located at the junction of the stomach and small intestine and plays a crucial role in regulating the exit of food.
- **Option 3: Villi**: Villi are small, finger-like projections in the small intestine that increase the surface area for absorption of nutrients. They do not regulate the exit of food from the stomach.
- **Option 4: All of these**: Since not all the options are correct, this option cannot be correct.

3. **Identifying the Correct Answer**: Based on the analysis, the sphincter muscles, specifically the pyloric sphincter, are responsible for regulating the exit of food from the stomach into the small intestine. Therefore, the correct answer is **Option 2: Sphincter Muscles**.

### Final Answer:
The structure that regulates the exit of food from the stomach into the small intestine is the **sphincter muscles** (specifically the pyloric sphincter).

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