Which one of the following gas was not present in free form at the time life originated on earth?
Ammonia
Oxygen
Hydrogen
Methane
Dart in $1925 $ found the skull of a body whom he named
Anatomically and structurally different, but functionally similar structures are called
The cranial capacity of Java ape man was about
The origin of seeds in the land plants was achieved about $345 \;million$ years ago, in lineages recognised as ancestral to all more advanced vascular plants in