Did you know that every green plant on the earth is a kind of factory? Each one makes food from sunrise to sunset. As it produces food, a green plant gives off an invisible gas called oxygen.
Oxygen is a very important gas. People and animals must have oxygen to live. People and animals take in oxygen when they breathe. You might think that all the oxygen would soon be used up. It would be, if we didn’t have green plants! All day long, they put oxygen into the air.
People and animals give something back to plants, too. People and animals breathe out a gas called carbon dioxide. Plants need lots of carbon dioxide to make food for themselves.
Picture Credit : Google