Sea urchin and sea cucumber belong to Phylum .............

Answer

To answer the question, "Sea urchin and sea cucumber belong to Phylum .............", we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Organisms**: The question mentions two organisms: sea urchin and sea cucumber.

2. **Research the Classification**: Both of these organisms are marine animals. To classify them correctly, we need to look at their biological classification.

3. **Phylum Identification**: Sea urchins and sea cucumbers are known to belong to the same phylum. This phylum is characterized by certain features such as a hard, spiny skin and a water vascular system.

4. **Conclusion**: Based on the classification and characteristics, we conclude that both sea urchin and sea cucumber belong to the phylum **Echinodermata**.

### Final Answer:
Sea urchin and sea cucumber belong to Phylum **Echinodermata**.

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