Earth is the only (21) we know of in the universe that can support human life. (22) human activities are making the planet less fit to live on.As the western world (23) on consuming two-thirds of the world’s resources while half of the world’s population do so (24) to stay alive we are rapidly destroying the (25) resource we have by which all people can survive and prosper.Everywhere fertile soil is (26) built on or washed into the seA、Renewable resources are exploited so much that they will never be able to recover (27) . We discharge pollutants (28) the atmosphere without any thought of the consequences.As a (29) the planet’s ability to support people is being (30) at the very time when rising human numbers and consumption are (31) increasingly heavy demands on it. TheEarth’s (32) resources are there for us to use. We need food, water, air, energy, medicines, warmth, shelter and minerals to (33) us fed, comfortable, healthy and active. If we are sensible in how we use the resources they will (34) indefinitely.But if we use them wastefully and excessively they will soon run (35) and everyone will suffer.