下列句子中划线的成语运用正确的一项是  (         )

Rainforest also help to ____   the weather. When trees are cut down, it gets hotter. Besides, one quarter of our ____  come from plants. Many of these plants can be found only in rainforests. There is a lot that we have not learnt about rainforests. If we____ them, we will never find out.

In my opinion, our future____ saving the rainforests. We must tell more people how important rainforests are so that they will stop doing harm to them. We must protect the rainforests now. We have to act now to save our only home.

保护动物的多样性，要（　　）