Answer:
The earth is a vast ecosystem that was created by natural forces. Through mankind's touch this has drastically changed. A sort of butterfly effect occurs whenever man intervenes with nature. For example, building a dam stops water flow, dries up the river bed, and forces native animals to relocate or die. Everything that mankind has done to the earth hurts the natural course of how nature grows and flows. By doing this the earth has become poisoned, and therefore mankind is poisoning his home and himself.
Its six sentences but here you go. Modify to how it best suits you.