Answer:
D. bacteria feeding on the large volume of carp feces depleted the oxygen
Explanation:
In the context, it is given that in a small farm pond, the owner added 20 grass carp and feed them with the abundant plants and algae that is found on her pond. The carp grew large after many years but one summer the owner found the grass carps along with other fishes were dead.
The most possible explanation for the dead of the fishes in the pond because the bacteria feeds on the carp feces which depletes the dissolved oxygen present in the water. Thus the fishes could not breathe and were finally dead.
Therefore, the correct option is (D).
Answer: a scientific theory must be testable and capable of being proven false.
