Question

In organic farming, some blue-green algae can be used as biofertilisers because:

• A. They are photosynthetic
• B. They have mucilage
• C. They grow everywhere
• D. They can fix atmospheric nitrogen

Answer 1

The correct option is D

They can fix atmospheric nitrogen

Blue-green algae are prokaryotic algae that are free-living creatures. They are also known as cyanobacteria. They fix the atmospheric nitrogen in moist soils. They are normally found in symbiotic relationships with higher plants and one of the benefits of their association is that they help in increasing the fertility of the soil by fixing atmospheric nitrogen into nitrates.