Some blue green algae can be used as biofertilizer as they are

Options

A. Photosynthetic
B. Surrounded by mucilage
C. Growing every where
D. Capable of fixing nitrogen

Answer

**Step-by-Step Solution:**

1. **Understanding Blue-Green Algae**: Blue-green algae, also known as cyanobacteria, are photosynthetic microorganisms that can be found in various environments, including freshwater and marine ecosystems.

2. **Role as Biofertilizers**: Biofertilizers are substances that contain living microorganisms which promote plant growth by increasing the supply of nutrients to the host plant. Cyanobacteria are particularly valuable as biofertilizers.

3. **Nitrogen Fixation**: One of the key features of certain blue-green algae is their ability to fix atmospheric nitrogen. This means they can convert nitrogen gas (N₂) from the atmosphere into ammonia (NH₃), which is a form of nitrogen that plants can use.

4. **Specialized Cells**: Cyanobacteria have specialized cells called heterocysts that facilitate this nitrogen fixation process. Heterocysts create an anaerobic environment that is essential for the nitrogen-fixing enzyme, nitrogenase, to function.

5. **Nutrient Conversion**: Once nitrogen is fixed into ammonia, it can be further converted into nitrites (NO₂⁻) and nitrates (NO₃⁻) by the cyanobacteria. These forms of nitrogen can then be absorbed by plants and utilized for the synthesis of proteins and nucleic acids.

6. **Conclusion**: Therefore, the reason some blue-green algae can be used as biofertilizers is that they are capable of fixing nitrogen, making them an important resource for enhancing soil fertility and promoting plant growth.

**Final Answer**: Some blue-green algae can be used as biofertilizers as they are **capable of fixing nitrogen**.

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