Which one of the following is helpful in the improvement of soil?
(A)Insecticide
(B) Bio-fertilizer
(C) Yeast
(D) All of these
Which one of the following is helpful in the improvement of soil?
(A)Insecticide
(B) Bio-fertilizer
(C) Yeast
(D) All of these

(B) Bio-fertilizer

A biofertilizer is a substance that contains living microorganisms that colonise the rhizosphere or the interior of the plant and promote growth by increasing the supply or availability of primary nutrients to the host plant when applied to seeds, plant surfaces, or soil. [1] Biofertilizers add nutrients through natural processes such as nitrogen fixation, phosphorus solubilization, and plant growth stimulation via the synthesis of growth-promoting substances.