The conversion of nitrate to nitrous oxide and nitrogen gas is termed as

The concentration of nitrogen in the atmosphere remains constant due to:

What is the function of $Pseudomonas$ and $Thiobacillus$ in the $N_2$ cycle?

Which of the following diagrams correctly depicts the $N_{2}$-cycle?

Reaction carried out by $N_{2}$ metabolising microbes include:
$I.$ $2 NH_{3} + 3 O_{2} \rightarrow 2 NO_{2}^{-} + 2 H^{+} + 2 H_{2} O$
$II.$ $2 NO_{2}^{-} + O_{2} \rightarrow 2 NO_{3}^{-}$
Which of the following statements about these equations is not true?

The amount of nitrogen fixed electrochemically and photochemically is: