The environment is everything around us in the natural world. It is the earth, the air, rivers, lakes, forests and seas. These are 1 human beings depend on for a living.
All natural waste is 2 . Animal waste and dead bodies are broken down by small creatures, like those worms in the soil. This is their 3 . The carbon dioxide that people and animals breathe（呼吸）out is used by plants to breathe and help them 4 . Plants give out oxygen which people and animals need to breathe in. Plants 5 water through their roots. They pass it out through their leaves 6 moisture（水分）. This moisture, together with water vapour coming from rivers and seas, rises and turns into water droplets and forms clouds. Larger water droplets then fall down in the form of 7 . In this way, the water goes 8 to the earth, rivers and seas to be used again.
However, humans have made a lot of changes to the earth. The technology and industry have made life 9 , but they also produce a lot of new waste. Nature finds this new waste hard or 10 to recycle. Man shall deal with this problem before it is too late.
