When a pond becomes covered with algae growth, oxygen levels drop as the algae decays. This process is called A. respiration
B. deoxygenation
C. eutrophication D. photosynthesis

It’s C: eutrophication

Explanation: Can you go to my questions and see the 2 last one posted and answer then since I answered urs.

you can get banned on this website if you post your quizzes here. . . .

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.