Recent research argues that an atmosphere rich in oxygen is the most likely source of energy for complex life to exist anywhere in the Universe, thereby limiting the number of places life may exist.
Professor David Catling at Bristol University, along with colleagues at the University of Washington and NASA, contend that significant oxygen in the air and oceans is essential for the evolution of multicellular organisms, and that on Earth the time required for oxygen levels to reach a point where animals could evolve was almost four billion years.
Moderation Team
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