Question
Biology Question on Microbes in human welfare
Which of the following species does not have the ability to fix atmospheric nitrogen?
A
Azotobactor
B
Anabaena
C
Nostoc
D
Spirogyra.
Answer
Spirogyra.
Explanation
Solution
Members of kingdom monera - bacteria and cyanobacteria (blue green algae) have the ability to fix nitrogen. Azotobacter is a N2-fixing bacteria. Anabaena and Nostoc are heterocystous blue-green algae. The heterocysts are the sites of N2-fixation. Spirogyra is one of the commonest green algae. It has no function in nitrogen fixation.