Why is coelenteron called gastrovascular cavity?

Explanation

### Step-by-Step Solution:

1. **Definition of Coelenteron**: Coelenteron refers to the central cavity found in coelenterates (like jellyfish, corals, and sea anemones).

2. **Function of Coelenteron**: The coelenteron serves two primary functions: digestion and circulation. It is a hollow space where food is digested and nutrients are circulated throughout the organism.

3. **Lack of Specialized Structures**: Coelenterates are considered primitive organisms. They do not have a well-defined digestive system (like a complete gut) that separates the processes of digestion and circulation.

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