Question

Which one of the following organisms does not have the ability to fix atmospheric nitrogen?

• A. Nostoc
• B. Ulothrix
• C. Rhizobium
• D. Azotobacter

Answer 1

The correct option is B Ulothrix

Nitrogen assimilation is the formation of organic nitrogen compounds like amino acids from inorganic nitrogen compounds present in the environment. Organisms like plant, fungi and certain bacteria that cannot fix nitrogen gas depend on the ability to assimilate nitrate or ammonia for their needs.

So, the correct option is 'Ulothrix'.