Assessing the relationship between hypoxia and life on Earth, and implications for the search for habitable exoplanets
Atmospheric oxygen at the level of present-day Earth (21%) is generally regarded as permissive for the development and survival of complex multicellular life, such as animals. The hypothesis that oxic conditions are conducive for multicellular life has subsequently been applied to the search for life elsewhere in the universe, with planets exhibiting atmospheric oxygen of a similar level to Earth