Arms are highly fragile in

Options

A. Ophiothrix
B. Asterias
C. Antedon
D. All the above.

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks which organism has highly fragile arms. We need to analyze the given options to determine the correct answer.

2. **Analyzing the Options**:
- **Ophiothrix**: This organism is known as the brittle star. It has five long arms that are extremely fragile and can easily shed, either whole or in pieces.
- **Asterias**: Commonly known as the starfish, Asterias has thick and short arms, making them less fragile compared to Ophiothrix.
- **Antidone**: Similar to Asterias, Antidone also possesses thick and short arms, which are not fragile.

3. **Conclusion**: Based on the analysis, Ophiothrix (brittle star) is the only organism among the options that has highly fragile arms. Therefore, the correct answer is **Ophiothrix**.

4. **Final Answer**: The correct option is **Ophiothrix**.

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