The early atmosphere on earth was answers to choose from (may be more than one answer! ) : mostly carbon dioxide,
extremely cold,
poisonous,
full of oxygen, or
extremely hot?

The Earth was formed 4.6 billion years ago from mixes of hot gases and solids. During those days Earth almost had no atmosphere and its surface was molten. Through time the Earth cooled and the atmosphere formed consisting mainly of gases that spewed from volcanoes. The atmosphere was extremely hot, composed of hydrogen, sulfide, methane, and carbon dioxide that is 200 times more potent compared to today’s atmosphere. Half a billion years later, Earth started to cool and solidify its surface making it conducive for water collection and making life officially inhabit the planet.