Evolution is a process of

Evolution is a process by which the characteristics of living organisms change over many generations as traits are passed from one generation to the next.

Explanation:

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explanation:

b,bacteria convert nitrates

into nitrogen gas.

d,plants and animals take in

and use nitrogen compounds.

e,bacteria break down waste    

products and return nitrogen  

to the soil.

a,bacteria convert atmospheric

nitrogen to ammonia.

c,bacteria convert ammonia

to nitrites and nitrates.