Which is a marine protist ?

Options

A. Amoeba proteus
B. Pelomyxa
C. Noctiluca
D. Paramecium.

Answer

To answer the question "Which is a marine protist?" we will analyze the given options one by one.

### Step-by-Step Solution:

1. **Understanding Marine Protists**:
- Marine protists are unicellular eukaryotes that thrive in saltwater environments. They can be found in oceans, seas, and other saline habitats.

2. **Analyzing the Options**:
- **Option A: Amoeba proteus**
- Amoeba proteus is primarily found in freshwater environments such as ponds, lakes, and streams. Therefore, it is not a marine protist.

- **Option B: Pelomyxa**
- Pelomyxa is a genus of giant flagellar amoebae that typically inhabit anaerobic or microaerobic conditions in stagnant freshwater sediments. Thus, it is also not a marine protist.

- **Option C: Noctiluca**
- Noctiluca is a type of dinoflagellate known for its bioluminescence. It is found in marine environments, making it a marine protist.

- **Option D: Paramecium**
- Paramecium is a free-living organism that predominantly lives in freshwater environments. Therefore, it is not a marine protist.

3. **Conclusion**:
- After analyzing all the options, the only marine protist among the given choices is **Noctiluca**.

### Final Answer:
**Noctiluca** is the marine protist.

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