The first non-cellular form of life could have originated about $. . . . .$ years ago.
After about how many years of formation of earth, life appeared on this planet?
Urey -Miller's experiment mixture had the following except
Who first conducted experiment on evolution to prove biochemical origin of life?
$A$ : During evolution the early time period was without ozone layer.
$R$ : Ozone layer absorbs $U.V.$ rays to some extent.