(N/A) The first non-cellular life forms originated approximately $3$ billion years ago in the form of giant molecules such as $RNA$,proteins,and polysaccharides enclosed within a self-replicating metabolic capsule.
These capsules eventually developed the ability to reproduce their constituent molecules.
The first cellular form of life originated about $2000$ million years ago.
These were likely single-celled organisms that formed exclusively in an aquatic environment.
The theory of abiogenesis,which suggests that the first life forms arose gradually through evolutionary forces acting on non-living molecules,is widely accepted.
Consequently,once these single cells were formed,they evolved over time into the diverse and complex biodiversity observed today.