Plants take in water through their roots, light from the sun through their leaves, and carbon dioxide from the air. Through an amazing biochemical process they release oxygen as a by-product, while at the same time producing food. For us, that means we get to both breathe and eat.
This valuable work done by plants is essential to our survival. That’s why we need keep enough of the world green, so that plants can go on maintaining the life on the planet. Rain forests are a vital part of this cycle.
Here is a short video, explaining how photosynthesis works.