Before there were plants to give off oxygen, Haldane pointed out, this gas would have been absent from the atmosphere.
(plants; to give off; oxygen) (Haldane; pointed out; this gas would have been absent from the atmosphere; T:Before there were plants) Context(Haldane pointed out,List([45, 64))):(this gas; would have been; absent from the atmosphere)
Haldane pointed out,List([45, 64))
plants Haldane this gas
to give off pointed out would have been
oxygen
this gas would have been absent from the atmosphere T:Before there were plants
absent from the atmosphere