If you complete multiple trials of Ur experiment that is called

A: Repetition

B: Restitution

C: Replication

D: Repudiation

Hi There the correct A: Repetition

Explanation:

Because If you are completing more than once that means  you are repeating it

answer; i believe the correct answer is ( 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.