Bio-fertilizers has been in news recently, which of the following nutrients can be supplied by Bio-fertilizers?

1. (N) – Nitrogen
2. (P) – Phosphorous
3. (K) – Potassium

Which of the options given above is/are correct?
a) 1 only
b) 1 and 2 only
c) 1 and 3 only
d) 1, 2 and 3

Ans-[D] 

Explanation– A Bio-fertilizer is a substance which contains living or latent microorganisms which, when applied to seeds, plant surfaces, or soil, colonizes the rhizosphere or the interior of the plant and promotes growth by increasing the supply or availability of primary nutrients to the host plant. They accelerate certain microbial processes in the soil which augment the extent of availability of nutrients in a form easily assimilated by plants.

These bio-fertilizer are valuable in not only providing nutrients such as N,P, and K but also mobilizes native soil phosphorous and render it available to crops.