In flagella and cilia, the number of doublets present in the peripheral region of axoneme are

Options

A. 18
B. 20
C. 9
D. 2

Answer

To solve the question regarding the number of doublets present in the peripheral region of the axoneme in flagella and cilia, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure of Flagella and Cilia**:
- Both flagella and cilia have a core structure known as the axoneme, which is composed of microtubules arranged in a specific pattern.

2. **Identify the Arrangement of Microtubules**:
- The axoneme typically has a "9+2" arrangement of microtubules. This means there are 9 doublets of microtubules arranged in a circle around 2 central microtubules.

3. **Focus on the Peripheral Region**:
- The question specifically asks for the number of doublets in the peripheral region of the axoneme. In the "9+2" arrangement, the peripheral region consists of the 9 doublets.

4. **Count the Doublets**:
- By counting, we find that there are indeed 9 doublets in the peripheral region of the axoneme.

5. **Conclusion**:
- Therefore, the answer to the question is that there are **9 doublets** present in the peripheral region of the axoneme in flagella and cilia.

### Final Answer:
The number of doublets present in the peripheral region of the axoneme in flagella and cilia is **9**.

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