Name the animal having both setae and nephridia

Options

A. Sea Urchin
B. Sea Mouse
C. Sea Anemone
D. Sea Pen.

Answer

To answer the question "Name the animal having both setae and nephridia," we can follow these steps:

### Step 1: Understand the Terms
- **Setae**: These are bristle-like structures found on the bodies of certain animals, particularly in the phylum Annelida. They assist in locomotion and movement.
- **Nephridia**: These are excretory organs that help in the removal of nitrogenous wastes from the body.

### Step 2: Identify the Phylum
- Both setae and nephridia are characteristic features of animals belonging to the phylum **Annelida**. This phylum includes segmented worms such as earthworms and polychaetes.

### Step 3: Evaluate the Options
- **Option 1: Sea Urchin**: This is a member of the phylum Echinodermata, which does not have setae or nephridia. So, this option is incorrect.
- **Option 2: Sea Mouse**: This is a type of polychaete worm that belongs to the phylum Annelida. It possesses both setae and nephridia, making this option correct.
- **Option 3: Sea Anemone**: This is a member of the phylum Cnidaria and does not have setae or nephridia. Hence, this option is incorrect.
- **Option 4: Sea Pen**: This is also a cnidarian and does not possess setae or nephridia. Thus, this option is incorrect.

### Step 4: Conclusion
Based on the analysis of the options, the animal that has both setae and nephridia is the **Sea Mouse** (Option 2).

### Final Answer
**The animal having both setae and nephridia is the Sea Mouse.**

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