Trees are the most useful things in the world. Children play under them. Travellers rest in their cool shade. Trees give us fruit to eat and firewood to burn. We build houses and make furniture with the wood of the trees. We need trees for our lives. If there were no trees, there would be no life on earth. Living things (people and animals) breathe in air. They breathe in oxygen from the air and breathe out carbon dioxide. If all the oxygen in the air was used up leaving only carbon

If all the oxygen in the air was used up leaving only carbon dioxide, what would happen to all of us? Everyone would die. But trees help us to live. They breathe in the carbon dioxide from the air and let oxygen out into the air. With the help of the sunlight, they break up carbon dioxide into carbon and oxygen. They use the carbon to make starch and let the oxygen out into the air.