Primitive organisms needed to develop defensive mechanisms that would protect them from oxygen toxicity and assure their survival.
(defensive mechanisms; would protect; them; from oxygen toxicity) (defensive mechanisms; assure; their survival) (Primitive organisms; needed; to develop defensive mechanisms) Context(Primitive organisms needed,List([0, 26))):(Primitive organisms; needed to develop; defensive mechanisms that would protect them from oxygen toxicity and assure their survival)
Primitive organisms needed,List([0, 26))
defensive mechanisms defensive mechanisms Primitive organisms Primitive organisms
would protect assure needed needed to develop
them from oxygen toxicity
their survival
to develop defensive mechanisms
defensive mechanisms that would protect them from oxygen toxicity and assure their survival