In Pheretima, septa are absent between which segments

Options

A. 3/4 and 9/10
B. 4/5 and 8/9
C. 5/6 and 7/8
D. 6/7 and 7/8

Answer

To solve the question "In Pheretima, septa are absent between which segments?" we will follow these steps:

### Step-by-Step Solution:

1. **Understand the Organism**: Pheretima, commonly known as the earthworm, belongs to the class Annelida. Annelids are characterized by their segmented bodies.

2. **Identify the Structure**: The body of earthworms is divided into segments both internally and externally. These segments are separated by structures known as septa (singular: septum).

3. **Determine the Segments**: The question asks about the absence of septa between specific segments. We need to identify where these septa are absent.

4. **Analyze the Segments**:
- It is known that in Pheretima, the coelom (body cavity) of the first four segments is continuous, meaning there are no septa dividing them.
- Additionally, septa are also absent between the ninth and tenth segments.

5. **Evaluate the Options**:
- Option 1 states that septa are absent between segments 3-4 and 9-10.
- Other options mention different segment pairs which do not align with the known structure of Pheretima.

6. **Conclusion**: Based on the analysis, the correct answer is Option 1: septa are absent between segments 3-4 and 9-10.

### Final Answer:
**The correct option is 1: septa are absent between segments 3-4 and 9-10.**

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