What compound is this?
Carbohydrates
Lipids
Nucleic acids
Proteins

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.

answer by yourhope:

answer is

human impact on the environment can be seen in the deterioration of the !

: )