Which of the following is used as an argument to stop extracting tropical rain forest resources?
a. growing countries must push their frontiers and develop their resources. b. medical treatments come from many sources and don't require the use of naturally growing species from the tropical rainforest.
c. there's tremendous biodiversity in the plant life of the tropical rain forest. d. there's no conclusive evidence that tropical rain forest clearing will permanently change the biodiversity of the earth as a whole.