In my related article I explained there is an epoch in the Earth’s history termed the “Great Oxygenation Event.” It happened a long time ago, roughly 350 million years ago, when much of today’s coal beds in the earth’s rocks began forming. 
It all began with one simple and then-new invention by Mother Nature. That invention has been truly great and everlasting; it’s widely known under the term PHOTOSYNTHESIS.
Photosynthesis
Photosynthesis (PS) is the process by which algae and plants convert carbon dioxide (CO2) to organic matter, like the wood of trees. Any other organism on this planet that is not an alga or plant itself feeds on the former. Therefore, CO2 is the source of all life on earth. There is not a single organism that does not require the carbon atom as a basic building block.
Photosynthesis brings about another product, rarely mentioned but vital to all higher organisms on the planet, and that is molecular oxygen (O2). There is no other source of O2 on earth but photosynthesis. Therefore, without carbon dioxide there also would be no free oxygen in our atmosphere.















