Which of the following statement is incorrect for echinoderms ?

Options

A. The most distinctive feature of echinoderms is the presence of water vascular system , which is a part of the coelem.
B. The main function of water vascular system is locomotion and the caputre of food.
C. Echinoderms have no proper excretory system .
D. They have well- developed circulatory system.

Answer

To determine which statement is incorrect for echinoderms, let's analyze each option step by step:

1. **Statement A**: "The most distinctive feature of echinoderm is the presence of water vascular system which is a part of the coelom."
- **Analysis**: This statement is correct. Echinoderms are indeed characterized by their water vascular system, which is a unique feature and part of their coelomic structure.

2. **Statement B**: "The main function of water vascular system is locomotion and the capture of food."
- **Analysis**: This statement is also correct. The water vascular system plays a crucial role in locomotion (movement) and in the feeding process of echinoderms.

3. **Statement C**: "Echinoderms have no proper excretory system."
- **Analysis**: This statement is correct. Echinoderms do not have a specialized excretory system; instead, they excrete waste products through their body surface.

4. **Statement D**: "They have well developed circulatory system."
- **Analysis**: This statement is incorrect. Echinoderms possess an open circulatory system, which is not considered well-developed compared to other animal phyla that have a closed circulatory system.

Based on the analysis, the incorrect statement about echinoderms is:

**Answer**: Option D - "They have well developed circulatory system."

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