Which of the following are protozoans?

Options

A. Diatoms , chlamydomonas , paramecium
B. Desmids, chlamydomonas, paramecium
C. Amoeba , paramecium , plasmodium
D. Amoeba , paramecium ,chlamydomonas, plasmodium

Answer

To determine which of the given options contains protozoans, we need to understand what protozoans are and identify them among the options provided.

### Step-by-Step Solution:

1. **Define Protozoans**: Protozoans are single-celled eukaryotic organisms. They can be free-living or parasitic and are characterized by their motility and lack of a cell wall.

2. **Identify the Options**: The options provided are:
- Option 1: Diatoms, Chlamydomonas, and Paramecium
- Option 2: Decimates, Chlamydomonas, and Paramecium
- Option 3: Amoeba, Paramecium, and Plasmodium
- Option 4: Amoeba, Paramecium, Chlamydomonas, and Plasmodium

3. **Analyze Each Option**:
- **Option 1**:
- Diatoms are not protozoans; they are a type of algae.
- Chlamydomonas is also not a protozoan; it is a green algae.
- Paramecium is a protozoan.
- **Conclusion**: This option is incorrect.

- **Option 2**:
- Decimates is not a recognized group in this context (possibly a typo).
- Chlamydomonas is not a protozoan.
- Paramecium is a protozoan.
- **Conclusion**: This option is incorrect.

- **Option 3**:
- Amoeba is a protozoan.
- Paramecium is a protozoan.
- Plasmodium is a protozoan (causes malaria).
- **Conclusion**: This option is correct.

- **Option 4**:
- Amoeba is a protozoan.
- Paramecium is a protozoan.
- Chlamydomonas is not a protozoan.
- Plasmodium is a protozoan.
- **Conclusion**: This option is incorrect due to the presence of Chlamydomonas.

4. **Final Answer**: The correct option that contains only protozoans is **Option 3: Amoeba, Paramecium, and Plasmodium**.