The first life on Earth was ...... .

Which scientists experimentally proved that organic molecules were produced based on evolution?

Given below are some major events in the early history of life:
$I.$ First heterotrophic prokaryotes
$II.$ First eukaryotes
$III.$ First autotrophic prokaryotes
$IV.$ First animals
Choose the correct sequence of these evolutionary events.

When did life originate on Earth?

The primitive or early atmosphere was composed of which mixture?

$A$ : During evolution,the early time period was without an ozone layer.
$R$ : The ozone layer absorbs $U.V.$ rays to some extent.