Rolling alga is

Options

A. Volvox
B. Chlamydomonas
C. Chlorella
D. Spirogyra.

Answer

**Step-by-Step Text Solution:**

1. **Understanding the Question**: The question asks about "rolling alga," which refers to a specific type of algae known for its unique rolling behavior.

2. **Identifying the Options**: The options provided are:
- Walwus
- Chlamydomonas
- Chlorella
- Spirogyra

3. **Analyzing Each Option**:
- **Walwus**: Known as rolling alga because it forms a spherical structure that rolls.
- **Chlamydomonas**: A unicellular green alga, but does not form rolling structures.
- **Chlorella**: Another unicellular green alga, known for its high chlorophyll content, but does not roll.
- **Spirogyra**: A filamentous green alga, which does not exhibit rolling behavior.

4. **Conclusion**: Based on the analysis, the only option that describes an alga that forms a rolling ball structure is Walwus. This structure is pale green and can roll due to its unique morphology.

5. **Final Answer**: Therefore, the correct answer is **Walwus**.

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