Find the odd one.

Options

A. Sea lily
B. Sea fan
C. Sea cucumber
D. Sea urchin

Answer

To solve the question "Find the odd one," we will analyze the given options one by one.

### Step 1: Identify the options
The options provided are:
1. Sea lily
2. Sea fan
3. Sea cucumber
4. Sea urchin

### Step 2: Classify the organisms
Next, we need to classify each of these organisms based on their phylum:
- **Sea lily**: This belongs to the phylum Echinodermata.
- **Sea fan**: This belongs to the phylum Cnidaria.
- **Sea cucumber**: This also belongs to the phylum Echinodermata.
- **Sea urchin**: This belongs to the phylum Echinodermata.

### Step 3: Compare the classifications
Now, we can summarize the classifications:
- Sea lily: Echinodermata
- Sea fan: Cnidaria
- Sea cucumber: Echinodermata
- Sea urchin: Echinodermata

### Step 4: Identify the odd one out
From the classifications, we can see that:
- Sea lily, sea cucumber, and sea urchin are all members of the phylum Echinodermata.
- Sea fan is the only organism that belongs to the phylum Cnidaria.

### Conclusion
Thus, the odd one out is **Sea fan** (Option 2).

### Final Answer
The correct answer is **Option 2: Sea fan**.

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