Which organisms actively participate in the nitrogen cycle in nature?

Select the correct matches.
$I$ Nitrosomonas - Nitrite to nitrate
$II$ Thiobacillus - Denitrification
$III$ Nostoc - Free-living nitrogen-fixer
$IV$ Azotobacter - Anaerobic nitrogen-fixer

Which bacteria is responsible for the reduction of nitrates into nitrogen in soil?

Which option is correct to match section $A$ with section $B$?

Section $A$	Section $B$
$(i)$ Nitrosomonas	$(a)$ Nitrite $\rightarrow$ Nitrate
$(ii)$ Agrobacterium	$(b)$ Nitrogen fixative bacteria
$(iii)$ Rhizobium	$(c)$ $NO_3^- \rightarrow N_2$
$(iv)$ Nitrobacter	$(d)$ Ammonia $\rightarrow$ Nitrite
	$(e)$ Denitrifying bacteria

Which of the following is true for nitrogen fixation?

The nature of $Bacillus \ rimosus$ is: