Figure given below refers to the nitrogen cycle

Which of the folowing is NOT part of the natural nitrogen cycle.

Options

A. Fossil fuels
B. Biological fixation
C. Lightening
D. Decomposition

Answer

A

Explanation

Nitrogen fixation occurs in following ways :
* Lightening: In nature lightening and ultraviolet radiations provide enough energy allow nitrogen to combine with oxygen in order to form nitrogen oxides.
* Industrial fixation: Industrial combustion, automobile exhausts are also sources of atmospheric nitrogen oxides.
* Biological nitrogen fixation: By some living organisms.