Everybody knows that we have only one earth on which we share with different kinds of animals and plants.With the development of the industry,we,the human beings,have produced more and more pollutions whci are harmful to the animals,plants and ourselves as well.The most serious problem that we have to face is that the earth is being destroyed by our so-called civilizations.Sometimes,you may find we are having more and more natural disasters on the earth.That is why some countries,like America,has begun to explore the Mars and the other planets.Remember,to save the earth is to save ourselves.
