All of the following are echinoderms, except

Options

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

Explanation

To solve the question "All of the following are echinoderms, except," we need to identify which of the given options does not belong to the phylum Echinodermata. Here’s a step-by-step solution:

### Step 1: Understand Echinoderms
Echinoderms are marine animals that belong to the phylum Echinodermata. They are characterized by their spiny skin and include organisms such as sea stars, sea urchins, and sea cucumbers.

### Step 2: Analyze the Options
We need to evaluate each option provided to determine if it is an echinoderm or not.

1. **C. Lily**: This is also known as Antidone and belongs to the class Tyrannoidae. Since it is classified under Echinodermata, this option is not the answer.

2. **C. Cucumber**: Sea cucumbers are indeed echinoderms and belong to the class Holothuroidea. Therefore, this option is also not the answer.

3. **C. Hair**: This option does not correspond to any known echinoderm. It is not a member of the Echinodermata phylum. Thus, this is a potential answer.

4. **C. Urchin**: Sea urchins are classic examples of echinoderms and belong to the class Echinoidea. Hence, this option is also not the answer.

### Step 3: Conclusion
After evaluating all the options, we find that the only option that is not an echinoderm is **C. Hair**. Therefore, the correct answer is option number 3.

### Final Answer:
**C. Hair** is not an echinoderm.

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