Metamerism is characteristic of phylum

Options

A. Platyhelminthes
B. Annelida
C. Porifera
D. Mollusca

Answer

**Step-by-Step Solution:**

1. **Understand the term "Metamerism":** Metamerism refers to the segmentation of the body into repeated units or segments. This is a key feature in certain animal phyla where organs and structures are repeated in each segment.

2. **Identify the phyla listed in the question:**
- **Platyhelminthes:** These are flatworms and do not exhibit metamerism; they have a simple body structure without segmentation.
- **Annelida:** This phylum includes segmented worms such as earthworms and leeches, which exhibit clear metamerism with repeated segments.
- **Porifera:** These are sponges, which do not have a segmented body plan and therefore do not exhibit metamerism.
- **Mollusca:** This phylum includes snails, clams, and octopuses, which do not display metamerism as their body structure is not segmented.

3. **Conclusion:** Among the options provided, the only phylum that exhibits metamerism is **Annelida**.

4. **Final Answer:** Metamerism is characteristic of phylum **Annelida**.

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