Acell memebrane is very specific about what it allows across how does this the cell

It allows in the good things such as minerals and carbohydrates, but it also keeps viruses out of the cell and sends white blood cells to kill the virus

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; i believe the correct answer is (a)0