The phylum name Annelida is based on -

Options

A. Nephridia
B. Metameres / segments
C. Parapodia
D. Antenna

Answer

### Step-by-Step Solution:

1. **Understanding the Phylum Annelida**: The phylum Annelida includes segmented worms, which are characterized by their body structure.

2. **Identifying Key Features**: Annelids have a body that is divided into multiple segments, also known as metamers. Each segment is a repeated unit that contributes to the overall structure of the organism.

3. **Etymology of the Name**: The name "Annelida" is derived from the Latin word "annulus," which means "little ring." This reflects the segmented nature of these organisms, where each segment can be thought of as a small ring.

4. **Conclusion**: Therefore, the phylum Annelida is named based on its characteristic feature of having a segmented body, which can be described as being made up of small rings or segments.

### Final Answer:
The phylum name Annelida is based on its characteristic of having a segmented body, derived from the Latin word "annulus," meaning small ring.

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