In $1885$,Frank discovered . . . . . . .

$VAM$ is

The common nitrogen fixer found in paddy fields is . . . . . . .

Blue-green algae increase which of the following in the soil?

Which microorganism is used as a biofertilizer in paddy fields?

Mycorrhiza is a symbiotic association between which of the following?
$(i)$ Fungi of the genus $Glomus$
$(ii)$ $Rhizobium$
$(iii)$ Root nodules of leguminous plants
$(iv)$ Cyanobacteria
$(v)$ Roots of higher plants
$(vi)$ Paddy fields