Which of the following two cycles are the most closely related in their role in sustaining life?
a. carbon and nitrogen
b. water and nitrogen
c. carbon and oxygen
d. nitrogen and phosphorus select the best answer from the choices provided a b c d

d. nitrogen and phosphorus

Nitrogen and phosphorus are important component of the genetic material present in the living organism, required for the expression of genes to perform a desire function in the living organisms. Both nitrogen and phosphorus are chief ingredients of the fertilizers required for the plant growth. Hence, nitrogen and phosphorous are two cycles that are most closely related in their role in sustaining life.

it is the most commonly accepted one

you didnt put any of the following