Parrotfish rely on corals for protection and shelter. Look at the parrotfish population over time. Why did the parrotfish population increase at first and then later decline?

1 and 6 for apex

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.

there are so many examples for that in different areas, like biology experiment carried out in our lab recently.

here's one link: