a large decrease in resistance is seen in the blood vessels supplying working skeletal muscle during exercise. what is the effect of this?

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.

the answer is d p: cell, q: organ, r: organ system, s: tissue

if you listed your answers right then i believe your answer is b.