Comb plates are found in

Options

A. adamsia
B. aurelia
C. hydra
D. pleurobrachia

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks where comb plates are found among the given options: A. Adamsia, B. Aurelia, C. Hydra, D. Pleurobrachia.

2. **Identifying Comb Plates**: Comb plates are specialized structures used for locomotion in certain marine organisms.

3. **Analyzing the Options**:
- **A. Adamsia**: This is a type of sea anemone and does not have comb plates.
- **B. Aurelia**: This is a jellyfish (moon jelly) and also does not possess comb plates.
- **C. Hydra**: This is a freshwater organism and does not have comb plates.
- **D. Pleurobrachia**: This is a type of ctenophore (comb jelly) that is known for having comb plates.

4. **Conclusion**: Based on the analysis, comb plates are found in **D. Pleurobrachia**.

5. **Additional Information**: Pleurobrachia belongs to the phylum Ctenophora (commonly known as comb jellies or sea walnuts) and is characterized by having eight rows of ciliated comb plates that aid in locomotion. These organisms are exclusively marine, exhibit radial symmetry, and are diploblastic with a tissue level of organization.