The following outline is provided as an overview of and topical guide to life forms: A life form (also spelled life-form or lifeform) is an entity that is living,[1][2] such as plants (flora), animals (fauna), and fungi (funga).
It is estimated that more than 99% of all species that ever existed on Earth, amounting to over five billion species,[3] are extinct.
[4][5] Earth is the only celestial body known to harbor life forms.
No form of extraterrestrial life has yet been discovered.
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