Which is a coelenterate

Options

A. Balanoglossus
B. Physalia
C. Sycon
D. Branchiostoma.

Answer

To determine which organism is a coelenterate (or cnidarian), we will analyze the given options based on their classification.

### Step-by-Step Solution:

1. **Understand the Term "Coelenterate":**
- Coelenterates, also known as cnidarians, belong to the phylum Cnidaria. They are characterized by having two germ layers (diploblastic), radial symmetry, and tissue-level organization.

2. **Analyze the Options:**
- **Option A: Blanoglossus**
- Blanoglossus is a member of the phylum Hemichordata, not Cnidaria. Therefore, it is not a coelenterate.

- **Option B: Physalia**
- Physalia, commonly known as the Portuguese man-of-war, is a well-known member of the phylum Cnidaria. It is indeed a coelenterate.

- **Option C: Cycone**
- Cycone is a member of the phylum Porifera, which includes sponges. Therefore, it is not a coelenterate.

- **Option D: Branchiostoma**
- Branchiostoma is a member of the phylum Chordata and is known as amphioxus or the lancelet. Thus, it is not a coelenterate.

3. **Identify the Correct Answer:**
- Based on the analysis, the only organism that belongs to the phylum Cnidaria (coelenterate) is **Physalia** (Option B).

### Conclusion:
The correct answer to the question "Which is a coelenterate?" is **Physalia**.

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