Water vascular system is a a trait of

Options

A. Porifers
B. Molluscs
C. Echinoderms
D. Arthropods.

Answer

**Step-by-Step Solution:**

1. **Identify the Trait in Question**: The question asks about the water vascular system and which phylum it is characteristic of.

2. **Define the Water Vascular System**: The water vascular system is a unique feature that functions in locomotion, feeding, and respiration in certain organisms.

3. **Identify the Relevant Phylum**: The water vascular system is specifically found in echinoderms, which include organisms such as starfish, sea urchins, and sea cucumbers.

4. **Describe Echinoderms**: Echinoderms are known for their spiny bodies, which are due to calcareous ossicles beneath their skin. This gives them a distinctive appearance.

5. **Explain the Functionality**: The water vascular system consists of a network of canals and tube feet that operate using hydraulic pressure. The madreporite is a key structure that regulates water flow into the system.

6. **Differentiate from Other Phyla**: Other phyla such as Porifera (sponges) have a water canal system, while Mollusca and Arthropoda do not possess a water vascular system.

7. **Conclude with the Correct Answer**: Therefore, the water vascular system is a trait of the phylum Echinodermata.

**Final Answer**: The water vascular system is a trait of Echinodermata.

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