Give the basis of which phylum coelenterata has been sub-divided.

Explanation

### Step-by-Step Solution:

1. **Introduction to Phylum Coelenterata**:
- Coelenterata, also known as Cnidaria, is a significant phylum within the animal kingdom. It includes a diverse range of aquatic animals.

2. **Subdivisions of Coelenterata**:
- The phylum Coelenterata is subdivided into three main classes: Hydrozoa, Scyphozoa, and Anthozoa.

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