Stone canal of Star Fish is

Options

A. Straight
B. Rounded
C. Pentangular
D. S-shaped.

Answer

**Step-by-Step Solution:**

1. **Understanding the Structure**: The stone canal is a part of the water vascular system in starfish, which is crucial for their locomotion and other functions.

2. **Identifying the Composition**: The stone canal is made up of calcareous materials, which are important for its structural integrity.

3. **Function of the Stone Canal**: The primary functions of the stone canal include aiding in locomotion, respiration, and the movement of water within the starfish's body.

4. **Analyzing the Shape**: The shape of the stone canal is a key aspect of the question. Upon analysis, it can be described as somewhat S-shaped.

5. **Conclusion**: Based on the analysis, the correct answer to the question regarding the shape of the stone canal in starfish is that it is S-shaped.

**Final Answer**: The stone canal of starfish is S-shaped (Option D).

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