To which class space alga Chlorella belongs

Options

A. Cyanophyceae
B. Rhodophyceae
C. Phaeophyceae
D. Chlorophyceae.

Answer

### Step-by-Step Solution:

1. **Identify the Organism**: The question asks about the class to which the space alga Chlorella belongs.

2. **Understand Chlorella**: Chlorella is a genus of green algae. It is important to note that it is recognized for its unicellular structure and is typically spherical in shape.

3. **Classify Chlorella**: Chlorella is classified under the class Chlorophyceae, which is the class of green algae. This classification is based on its characteristics and the presence of chlorophyll pigments.

4. **Evaluate the Options**:
- **Cyanophyceae**: This class includes blue-green algae, which are not true algae but are prokaryotic organisms (cyanobacteria). Thus, this option is incorrect.
- **Rhodophyceae**: This class consists of red algae, which is not related to Chlorella. Hence, this option is also incorrect.
- **Phaeophyceae**: This class includes brown algae, which again does not include Chlorella. Therefore, this option is incorrect as well.
- **Chlorophyceae**: This is the correct option as it encompasses green algae, including Chlorella.

5. **Conclusion**: Based on the classification and evaluation of options, Chlorella belongs to the class **Chlorophyceae**.

### Final Answer:
Chlorella belongs to the class **Chlorophyceae**.

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