It's been a while, but i think the answer is D. I could be wrong though.
B.their uses for medicinal purposes I think. Not 100% sure.
Answer:
The fact about the Earth's rainforest is the most true is A. Half of the known plant varieties in the world are found in the rainforests.
In fact, even though the Earth's rainforests only cover approximately 7% of the Earth, it makes up approximately 50% of the population of living things.
Explanation: