Which of the following set of animals belogns to phylum Echinodermata?

Options

A. Ascaris, nereis, echinus
B. Cucumaria, adamsia, pinctada
C. Aplysia, antedon, liumulus
D. Echinus, asteria, ophiura

Explanation

To determine which set of animals belongs to the phylum Echinodermata, we will analyze the given options step by step.

### Step 1: Understand the Characteristics of Echinodermata
- Echinodermata is a phylum that includes marine organisms characterized by a hard, calcareous endoskeleton, radial symmetry, and a water vascular system. Common examples include sea stars, sea urchins, and sea cucumbers.

### Step 2: Analyze Each Option
1. **Ascaris**:
- Ascaris is a roundworm and belongs to the phylum Nematoda.
- **Conclusion**: Not Echinodermata.

2. **Nereus**:
- Nereus is a genus of polychaete worms and belongs to the phylum Annelida.
- **Conclusion**: Not Echinodermata.

3. **Echinus**:
- Echinus, commonly known as sea urchin, is indeed a member of the phylum Echinodermata.
- **Conclusion**: Belongs to Echinodermata.

4. **Cucumeria**:
- Cucumeria, also known as sea cucumber, belongs to the phylum Echinodermata.
- **Conclusion**: Belongs to Echinodermata.

5. **Adamasia**:
- Adamasia is a member of the phylum Coelenterata (Cnidaria).
- **Conclusion**: Not Echinodermata.

6. **Pinctada**:
- Pinctada is a genus of pearl oysters and belongs to the phylum Mollusca.
- **Conclusion**: Not Echinodermata.

7. **Aphelisia**:
- Aphelisia is a genus of mollusks.
- **Conclusion**: Not Echinodermata.

8. **Antedon**:
- Antedon is known as a feather star and belongs to the phylum Echinodermata.
- **Conclusion**: Belongs to Echinodermata.

9. **Limulus**:
- Limulus, known as the horseshoe crab, belongs to the phylum Arthropoda.
- **Conclusion**: Not Echinodermata.

10. **Aechinus**:
- Aechinus is another term for sea urchin, which is a member of the phylum Echinodermata.
- **Conclusion**: Belongs to Echinodermata.

11. **Asteria**:
- Asteria, commonly known as starfish, belongs to the phylum Echinodermata.
- **Conclusion**: Belongs to Echinodermata.

12. **Ophuria**:
- Ophuria, known as brittle stars, is also a member of the phylum Echinodermata.
- **Conclusion**: Belongs to Echinodermata.

### Step 3: Identify the Correct Set
- From the analysis, we can conclude that the following animals belong to the phylum Echinodermata:
- Echinus (sea urchin)
- Cucumeria (sea cucumber)
- Antedon (feather star)
- Aechinus (sea urchin)
- Asteria (starfish)
- Ophuria (brittle star)

### Final Conclusion
The set of animals that belong to the phylum Echinodermata includes Echinus, Cucumeria, Antedon, Aechinus, Asteria, and Ophuria.

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