our earth

Earth and plants. With earth, there won't be plants. Without plants, there won't be oxygen at all. We need plants and plants need us. We need the oxygen from them while they need the carbon dioxide from us. It's a co-existing relationship between mankind and plants. Without plants, there won't be mankind at all, unless everyone of us were to carry oxygen tank? Even so, there will only be limited supplies.

Yes buddy, the biggest contributer of oxygen to your planet is certainly your green trees and plants undergo photosynthesis. They use carbon dioxide produced by human respiration, water and sunlight for photo synthesis and produce oxygen with which we respire and live. I can't imagine life with green tees which is now depleting due to developments, technologies and many more. Lets save our mother earth from getting scared with deserts.