Trilobites were evolved during which of the following period

Which of the following is the correct sequence of events in the origin of life ?

$I.$ Formation of protobionts

$II.$ Synthesis of organic monomers

$III.$ Synthesis of organic polymers

$IV.$ Formation of $DNA$ ­based genetic systems

$A$ : There is $99\;\%$ homology in haemoglobin of man and Gorilla.
$R$ : Modern man is direct descendent of Gorilla.