Which of the following algae is not flagellated ?

Options

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

Explanation

To determine which of the following algae is not flagellated, we will analyze each option provided:

1. **Identify the Options**: The options given are:
- A. Volvox
- B. Spirogyra
- C. Dinoflagellates
- D. Chlamydomonas

2. **Analyze Each Option**:
- **A. Volvox**: This is a colonial green algae that is flagellated. It has flagella that help it move in water. Therefore, this option is flagellated.

- **B. Spirogyra**: This is a filamentous green algae that does not have flagella. It is unbranched and forms green mats in water bodies. Therefore, this option is not flagellated.

- **C. Dinoflagellates**: These are a group of protistian algae that are characterized by having two flagella. Hence, this option is also flagellated.

- **D. Chlamydomonas**: This is a unicellular green algae that is also flagellated, possessing two flagella for movement.

3. **Conclusion**: After analyzing all the options, we find that **B. Spirogyra** is the only algae listed that is not flagellated.

**Final Answer**: B. Spirogyra

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