Given below 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

The scientist related with the over throw or the "Theory of spontaneous generation'' and experiments with swan-necked flasks is

The best description of natural selection is

$A$ : Archaeopteryx had free caudal vertebrae and toothed beak with teeth like reptiles.
$R$ : It is missing link between reptiles and bird