The most important characteristic of phylum Cnidaria is

Options

A. Cnidoblasts
B. Choanocytes
C. Thesocytes
D. Archaeocytes

Answer

### Step-by-Step Solution:

1. **Understanding Phylum Cnidaria**:
- Phylum Cnidaria includes organisms such as jellyfish, corals, and sea anemones. They are primarily aquatic and exhibit radial symmetry.

2. **Identifying Key Characteristics**:
- The most significant feature of Cnidarians is the presence of specialized cells known as cnidocytes (or cnidoblasts).

3. **Function of Cnidocytes**:
- Cnidocytes are explosive cells that contain a specialized organelle called a nematocyst. This nematocyst can deliver a sting to other organisms, which is crucial for capturing prey and defense.

4. **Comparison with Other Options**:
- The question may provide other options such as choanocytes, thesocytes, and archaeocytes.
- Choanocytes are found in sponges and are involved in feeding.
- Thesocytes are also sponge cells involved in food storage.
- Archaeocytes are mobile cells in sponges with various functions.

5. **Conclusion**:
- Among all these characteristics, the presence of cnidocytes is unique to Cnidarians and is the most important characteristic of this phylum.

### Final Answer:
The most important characteristic of phylum Cnidaria is the presence of cnidocytes (or cnidoblasts).

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