Question

Forest are called the lungs of the world." explain

Answer 1

forest are called the lungs of the world because growing trees take in carbon dioxide and gives oxygen which is the vital role for humans because we cannot live without air

Answer 2

Forests are called lungs of world . As you know that humans need oxygen to live and world is owned by humans . Soil also depend upon trees because trees help in preventing soil erosion . Animals , reptiles  and humans are directly always depended on trees. So it is concluded that trees are most important part of world.