Grouping of algae is based on

Options

A. Food reserve
B. Colony formation
C. Shape
D. Pigments.

Answer

**Step-by-Step Solution:**

1. **Understanding Algae**: Algae are eukaryotic organisms that fall under the category of thalophytes. They are primarily aquatic and can perform photosynthesis.

2. **Grouping Criteria**: The grouping of algae is based on the presence of specific pigments. These pigments play a crucial role in determining the color and type of algae.

3. **Classes of Algae**: Algae are divided into three main classes:
- **Chlorophyceae**: Known as green algae, they contain chlorophyll A and B, which gives them their green color.
- **Phaeophyceae**: Known as brown algae, they contain chlorophyll A and C, along with an additional pigment called fucoxanthin, which gives them their brown color.
- **Rhodophyceae**: Known as red algae, they contain chlorophyll A and D, along with phycoerythrin, which is responsible for their red color.

4. **Conclusion**: Based on the presence of these pigments, algae can be classified into different groups. Therefore, the correct answer to the question is that the grouping of algae is based on pigments.

5. **Final Answer**: The correct answer is option D: Pigments.

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