Identify the odd one out in the context of biofertilizers.

Identify the correct statements regarding mycorrhiza:
$(1)$ Many members of the genus $Glomus$ form mycorrhiza.
$(2)$ It is responsible for all mineral absorption from the soil.
$(3)$ Such associations show benefits against drought and salinity in plants.
$(4)$ Mycorrhiza is a symbiotic association between fungi and roots of higher plants.

Select the appropriate option regarding mycorrhiza.

The main source of biofertilizers is:

The nitrogen-fixing microorganism associated with $Azolla$ in rice fields is .......

$A$ water fern, which is used as a green manure in rice fields is