watch 01:48 The Loop (TV) Do you like this video? Air was the mixture of gases that was breathed by biological lifeforms. An atmosphere was the type of air surrounding planets. Earth's atmosphere was approximately 80% nitrogen and 20% oxygen and was the habitable air composition for humans. (AUDIO: The Resurrection of Mars) Retrieved from "https://tardis.fandom.com/wiki/Air?oldid=2957558" Categories: Gases + cat Cancel Save Community content is available under CC-BY-SA unless otherwise noted.