The answer is D as there are fluctuations which means that changes in the population of one affects the population of the other. as prey pop increases predator pop increases leading to a decease in prey pop which causes predator pop to decrease due to lack of food then prey increases and the cycle repeats
I believe it's B. Apologies if I'm wrong.
Rare climate event caused by darwin finches of you look it up the whole article comes up on it
D. photosynthetic decomposers