Free swimming, radially symmetrical animals with cnidocytes belong to

Options

A. Coelenterata
B. Platyhelminthes
C. Ctenophora
D. Echinodermata

Answer

To solve the question about free swimming, radially symmetrical animals with cnidocytes, we can follow these steps:

### Step 1: Understand the Key Terms
- **Free swimming**: This indicates that the animals are motile and can move freely in water.
- **Radially symmetrical**: This means the body structure can be divided into similar halves by multiple planes passing through a central axis.
- **Cnidocytes**: These are specialized cells found in certain animals that contain nematocysts, which are used for capturing prey and defense.

### Step 2: Analyze the Options
1. **Coelenterata**: This group includes animals like jellyfish and sea anemones, which are known for their radial symmetry and the presence of cnidocytes.
2. **Platyhelminthes**: This group includes flatworms, which are not radially symmetrical and do not have cnidocytes.
3. **Ctenophora**: This group includes comb jellies, which are radially symmetrical but do not possess cnidocytes; instead, they have colloblasts.
4. **Echinodermata**: This group includes starfish and sea urchins, which are radially symmetrical but do not have cnidocytes.

### Step 3: Identify the Correct Group
Given the characteristics:
- Free swimming: Coelenterates, Ctenophores, and Echinoderms can be free swimming.
- Radially symmetrical: Coelenterates, Ctenophores, and Echinoderms are radially symmetrical.
- Cnidocytes: Only Coelenterata contains cnidocytes.

### Conclusion
Based on the analysis, the correct answer is **Coelenterata**.

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