In starfish , the stone canal is associated with

Options

A. Blood vascular system
B. canal system
C. Digestive system
D. Water vascular system

Answer

**Step-by-Step Solution:**

1. **Understanding the Structure**: In starfish, the stone canal is a part of the water vascular system. This system is crucial for various functions including locomotion, feeding, and respiration.

2. **Identifying Components**: The stone canal connects the madreporite (the entry point for water) to the ring canal. The madreporite allows water to enter the system, which is essential for the starfish's functioning.

3. **Function of the Stone Canal**: The primary function of the stone canal is to transport water from the madreporite to the ring canal. This connection is vital for the operation of the water vascular system.

4. **Understanding the Water Vascular System**: The water vascular system in starfish consists of the madreporite, stone canal, ring canal, and radial canals. This system helps in movement, feeding, and respiration.

5. **Eliminating Incorrect Options**:
- The blood vascular system is not present in starfish.
- The canal system is associated with Porifera, not Echinodermata.
- The digestive system is simple and primarily involves the ring canal, but it is not the main association of the stone canal.

6. **Conclusion**: Therefore, the stone canal is associated with the water vascular system in starfish.

**Final Answer**: The stone canal in starfish is associated with the water vascular system.

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