____allows only small amount of food to pass from stomach to duodenum.

Explanation

**Step-by-Step Text Solution:**

1. **Identify the Structure**: The question asks about a structure that allows only a small amount of food to pass from the stomach to the duodenum. The correct answer is the **pyloric sphincter**.

2. **Understand the Function of the Pyloric Sphincter**: The pyloric sphincter is a ring of smooth muscle located at the junction between the stomach and the duodenum (the first part of the small intestine). Its primary function is to regulate the flow of partially digested food (chyme) from the stomach into the duodenum.

3. **Role in Digestion**: The stomach performs partial digestion of food, mixing it with gastric juices. The pyloric sphincter controls the release of this mixture into the duodenum, ensuring that only a small amount of food passes through at a time. This is important because it allows for proper digestion and absorption in the small intestine.

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