Water vascular system is present in ________.

Explanation

**Step-by-Step Solution:**

1. **Identify the System**: The question asks about the water vascular system, which is a specific biological system found in certain organisms.

2. **Determine the Phylum**: The water vascular system is characteristic of a particular group of animals. This system is primarily associated with the phylum Echinodermata.

3. **Understand Echinodermata**: Echinodermata includes marine animals such as starfish, sea urchins, and sea cucumbers. They are known for their radial symmetry and unique water vascular system.

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