Question

How many of the following are the symbiotic nitrogen fixing micro-organisms?

Rhizobium, Anabaena, Frankia, Azotobacter, Nostoc, Clostridium, Beijerinckia, Klebsiella

Options

• 2

• 3

• 4

• 5

Answer 1

3

Explanation:

Anabaena, Frankia, and Rhizobium are examples of symbiotic N-fixing microbes. These are typically connected to subterranean components, such as the roots of higher plants.

Azotobacter, Nostoc, Clostridium, Beijerinckia, and Klebsiella are examples of free-living or non-symbiotic N-fixing microbes.