Question

which of the following gases was absent from earths early atmosphere?
oxygen
methane
carbon dioxide
hydrogen
helium

Explanation:

Earth's early atmosphere was formed from volcanic out - gassing and other processes. It contained methane, carbon dioxide, hydrogen, and helium. Oxygen was absent because there were no significant sources of oxygen - producing life forms like plants or cyanobacteria until later in Earth's history through the process of photosynthesis.

Answer:

Oxygen