Carbon doixide
oxygen
energy from the sun,lightening,earths heat triggered chemical reaction for the early gases of the earth combined
Early volcanoes discharged different combinations of gases into the Earth's atmosphere creating rain, which cooled the planet and formed solid land masses, and every other element discovered presently.
green plants / algae
They look at the mineral composition of the rocks. There are some minerals that can only form in the presence of oxygen.
What happened to all the water vapour in the early atmosphere
Methane gas
oxygen
yes
oxygen
Oxygen was the missing thing was.
oxygen
nitrogen
nitrogen
photosynthesis
no
photosynthsis
Photosynthesis by plants