Pentaradial symmetry occurs in

Options

A. Echinodermate
B. Arthropada
C. Mollusca
D. Annelida

Answer

**Step-by-Step Solution:**

1. **Understanding Pentaradial Symmetry:**
- Pentaradial symmetry refers to a body plan in which the body parts are arranged around a central axis in five distinct sections or rays. This type of symmetry is commonly observed in certain marine organisms.

2. **Identifying the Phyla:**
- The question provides four options: Echinodermata, Arthropoda, Mollusca, and Annelida. We need to determine which of these phyla exhibits pentaradial symmetry.

3. **Analyzing Each Option:**
- **Arthropoda:** Organisms in this phylum, such as insects and crustaceans, exhibit bilateral symmetry, not pentaradial symmetry.
- **Mollusca:** This phylum includes snails, clams, and squids, which also show bilateral symmetry.
- **Annelida:** Earthworms and leeches belong to this phylum, and they too display bilateral symmetry.
- **Echinodermata:** This phylum includes starfish (sea stars), sea urchins, and sea cucumbers, which are known for their pentaradial symmetry.

4. **Conclusion:**
- Based on the analysis, the only phylum that exhibits pentaradial symmetry is Echinodermata. For example, a sea star has five arms arranged around a central mouth, demonstrating this type of symmetry.

5. **Final Answer:**
- Therefore, the correct answer to the question is **Echinodermata**.

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