A unicellular organism often considered connecting link between plants and animals is

Options

A. Monocystis
B. Paramecium
C. Euglena
D. Entamoeba.

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for a unicellular organism that is often considered a connecting link between plants and animals. This implies that the organism should exhibit characteristics of both groups.

2. **Analyzing the Options**: The options given are:
- Monocystis
- Paramecium
- Euglena
- Entamoeba

3. **Identifying Characteristics**:
- **Monocystis**: A parasitic organism, primarily found in the reproductive organs of earthworms. It does not exhibit plant-like or animal-like characteristics.
- **Paramecium**: A ciliated protozoan that is heterotrophic and does not perform photosynthesis.
- **Euglena**: A flagellated unicellular organism that can perform photosynthesis (like plants) and can also absorb nutrients from the environment (like animals).
- **Entamoeba**: A genus of amoebas, typically parasitic and heterotrophic.

4. **Determining the Correct Answer**: Among the options, Euglena is unique because it can photosynthesize in the presence of sunlight (like plants) and can also feed on organic matter in the absence of light (like animals). This dual capability makes it a connecting link between the two kingdoms.

5. **Conclusion**: Therefore, the correct answer to the question is **Euglena**.

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