Match the following columns related to nitrogen cycle
$\begin{array}{cc}\text{Column - I}& \text{Column - II}\\ \text{A. Nitrogen fixation}& \text{1.Conversion of}N{H}_3\text{to}N{O}_3^{-}\\ \text{B. Nitrogen assimilation}& \text{2.Conversion of}N{O}_3^{-}\text{or}N{H}_3\text{to organic nitrogen}\\ \text{C. Ammonification}& \text{3.Conversion of}N{O}_3^{-}\text{to atmospheric nitrogen}\\ \text{D. Nitrification}& \text{4.Conversion of}{N}_{2}toN{O}_3^{-}\text{or}N{H}_3\\ \text{E. Denitrification}& \text{5.Conversion of organic nitrogen to}N{H}_3\end{array}$

The correct option is B

A - 4, B - 2, C - 5, D - 1, E - 3

Nitrogen cycle involves five steps- nitrogen fixation, nitrogen assimilation, ammonification, nitrification and denitrification. The product of one step is the substrate for the next step.

$\begin{array}{cc}\text{Column - I}& \text{Column - II}\\ \text{A. Nitrogen fixation}& \text{4.Conversion of}{N}_{2}toN{O}_3^{-}\text{or}N{H}_3\\ \text{B. Nitrogen assimilation}& \text{2.Conversion of}N{O}_3^{-}\text{or}N{H}_3\text{to organic nitrogen}\\ \text{C. Ammonification}& \text{5.Conversion of organic nitrogen to}N{H}_3\\ \text{D. Nitrification}& \text{1.Conversion of}N{H}_3\text{to}N{O}_3^{-}\\ \text{E. Denitrification}& \text{3.Conversion of}N{O}_3^{-}\text{to atmospheric nitrogen}\end{array}$