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

$BGA$ (Blue-Green Algae) is mostly used as a biofertilizer in which crop?

Which of the following is a fertilizer?

The symbiotic association of fungi of the genus $Glomus$ with plants leads to:

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.

Which of the following is not a major source of biofertilizers?