Which one of the following is not a characteristic of phylum Annelids?

Options

A. pseudocoelom
B. ventral nerve cord
C. closed circulatory system
D. segmentation

Answer

To determine which characteristic is not associated with the phylum Annelida, we can analyze the given options step by step.

### Step-by-Step Solution:

1. **Understand the Characteristics of Annelids**:
- Annelids are segmented worms that belong to the phylum Annelida. They have a true coelom (body cavity) and exhibit segmentation.

2. **Evaluate the Options**:
- **Option A: Pseudocoelomate**: This term refers to organisms that have a pseudocoelom, which is a body cavity that is not completely lined with mesoderm. Annelids are coelomates, meaning they have a true coelom. Therefore, this option is not a characteristic of Annelida.
- **Option B: Ventral Nerve Cord**: Annelids possess a ventral nerve cord, which is a characteristic feature of this phylum. Thus, this option is a characteristic of Annelida.
- **Option C: Closed Circulatory System**: Annelids, such as earthworms, have a closed circulatory system, which is another defining characteristic of this phylum. Therefore, this option is also a characteristic of Annelida.
- **Option D: Segmentation**: Segmentation is a key feature of Annelids, where the body is divided into segments. This option is a characteristic of Annelida.

3. **Conclusion**:
- Based on the analysis, the characteristic that is not associated with phylum Annelida is **Option A: Pseudocoelomate**.

### Final Answer:
**The characteristic that is not associated with phylum Annelida is Pseudocoelomate.**

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