Gastrovascular cavity or coelenteron partitioned in

Options

A. Hydrozoa
B. Scyphozoa
C. Actinozoa
D. Both B and C.

Answer

To answer the question regarding which class of Coelenterata (Cnidaria) has a partitioned gastrovascular cavity or coelenteron, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Terms**:
- The gastrovascular cavity, also known as coelenteron, is a central cavity in cnidarians where digestion occurs.
- The term "partitioned" refers to the presence of internal divisions or septa within this cavity.

2. **Identify the Classes of Cnidaria**:
- The question provides four options: Hydrozoa, Scyphozoa, Actinozoa, and both B and C.
- Hydrozoa includes small, often colonial organisms like hydras and Portuguese man o' war.
- Scyphozoa includes jellyfish, which have a simpler gastrovascular cavity structure.
- Actinozoa (now referred to as Anthozoa) includes sea anemones and corals.

3. **Analyze Each Class**:
- **Hydrozoa**: Generally does not have a partitioned gastrovascular cavity.
- **Scyphozoa**: Also lacks significant partitioning in their gastrovascular cavity.
- **Actinozoa (Anthozoa)**: This class is characterized by having a partitioned gastrovascular cavity, which is divided by structures called mesenteries.

4. **Conclude the Answer**:
- Based on the analysis, the class that has a partitioned gastrovascular cavity is **Actinozoa** (Anthozoa).

5. **Final Answer**:
- The correct answer is **Actinozoa** (option 3).