Question

All of the following are products of or contribute to the nitrogen cycle EXCEPT:

Question 22 options:

A)	formation of plant proteins from uptake of soil ammonium and nitrate compounds

B)	photosynthesis

C)	excretion of urea by mammals

D)	action of soybean root nodule bacteria

Answer 1

Nitrogen cycle involves any biomolecule which has nitrogen.

Nitrogen is present in the protein, so option A is the part of the nitrogen cycle.

Urea is made upon nitrogen. so option B is the part of the nitrogen cycle.

Root nodules bacteria are the symbiotic bacteria that fix atmospheric nitrogen, so that plant can utilize them. so option D is the part of the nitrogen cycle.

Overall reaction of photosynthesis is

CO2+ H2O = C6H12O6 + O2.

In this reaction, there is no involvement of nitrogen. so option B is not the part of the nitrogen cycle.

Hecne answer is option B- photosynthesis