When Earth formed<span> 4.6 billion years ago from a hot mix of gases and solids, it had almost no </span>atmosphere<span>. The surface was molten. As </span>Earth<span> cooled, an </span>atmosphere formed<span> mainly from gases spewed from volcanoes. It included hydrogen sulfide, methane, and ten to 200 times as much carbon dioxide as today's </span>atmosphere<span>. So it would be Outgassing. Hope that helped :)</span>
During aerobic cellular respiration, glucose reacts with oxygen, forming ATP that can be used by the cell. Carbon dioxide and water are created as byproducts.
