$A$ free-living anaerobic bacterium capable of $N_2$ fixation in soil is

The enzyme nitrogenase,present in the root nodules of leguminous plants,catalyzes the conversion of atmospheric nitrogen into which of the following products?

Which of the following pigments is essential for nitrogen fixation by leguminous plants?

Free-living bacteria that perform nitrogen fixation are found in .........

Nitrogen fixing genes are called

Identify the non-leguminous plants that form nodules to fix nitrogen.