The universe is a single system that consists of everything that physically exists. the basic principles of the universe, such as the conservation of mass, the conservation of energy, and the laws of gravity

100 dollars because yeah

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.