Answer: The evolution of the atmosphere that we inhabit today can be split into three main stages: the early atmosphere, ocean formation, and the biological era.
Step-by-step explanation:
When Earth formed 4.6 billion years ago from a hot mix of gases and solids, it had almost no atmosphere. The surface was molten. As Earth cooled, an atmosphere formed mainly from gases spewed from volcanoes. It included hydrogen sulfide, methane, and ten to 200 times as much carbon dioxide as today's atmosphere