_____ is the smallest part of small intestine

Answer

To answer the question "_____ is the smallest part of the small intestine," we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure of the Small Intestine**: The small intestine is a crucial part of the digestive system where most of the digestion and absorption of nutrients occurs. It consists of three main sections: the duodenum, jejunum, and ileum.

2. **Identify the Parts of the Small Intestine**:
- **Duodenum**: This is the first part of the small intestine, connecting it to the stomach. It is relatively short.
- **Jejunum**: This is the middle section of the small intestine and is longer than the duodenum.
- **Ileum**: This is the final and longest part of the small intestine.

3. **Compare the Lengths of Each Part**:
- The duodenum is approximately 20 to 25 centimeters long.
- The jejunum is about 2.5 meters long.
- The ileum is around 3 meters long.

4. **Determine the Smallest Part**: Based on the lengths provided, the duodenum is the shortest segment of the small intestine, measuring only 20 to 25 centimeters.

5. **Conclusion**: Therefore, the answer to the question is that the **duodenum** is the smallest part of the small intestine.

### Final Answer:
**Duodenum**