The answer is either B or D. Letter A doesn't make sense and letter C isn't right either because you need rainfall to have fertile plains.
Answer:
area of land dropping steeply towards deep ocean basins
There's actually an entire documentary made about this certain fish, its name is Parrot Fish.
The reason for its name is because it has a beak, which it uses to bite and eat through coral.
And at the end of the day, when the fishes poop, it turns into sand.
For example, one 2010 study in Marine Biology found that large parrotfish in Hawaii can churn out 840 pounds of eroded coral—i.e. white sand—per year. A single giant humphead parrotfish can produce 11,000 pounds of sand per year.
hope this helps!
B) Granite is an igneous rock.
The capital of Siberia is Novosibirsk
