On Earth, about 21 % of the air is oxygen, which humans need in order to breath.
(about 21 % of the air; is; oxygen, which humans need in order; L:On Earth) (oxygen; need; in order) Context(oxygen need,List([35, 60))):(humans; to breath; )
oxygen need,List([35, 60))
about 21 % of the air oxygen humans
is need to breath
oxygen, which humans need in order L:On Earth
in order