Nitrogen fixation is one-way nitrogen moves through ecosystems. Why is nitrogen fixation necessary for ecosystems? A. Nitrogen fixation converts nitrogen gas into carbohydrates.
B. Nitrogen fixation returns nitrogen gas to the atmosphere.
C. Nitrogen fixation allows nitrogen gas to be dissolved in water.
D. Nitrogen fixation converts nitrogen gas to ammonia.

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.

c is the correct answer hope this !

only about ten percent of the energy at one trophic level is passed on to organisms at the next trophic level. the remainder of the energy is used in life processes or lost as heat.