If … there weren’t any selectable variants that ….
Exactly- There have never been selectable variants that are immortal (or even nearly so). Whether that is because immortality is hard (unlikely to result from random drift) or not is irrelevant for the purposes of natural selection if it never happens.
Exactly- There have never been selectable variants that are immortal (or even nearly so). Whether that is because immortality is hard (unlikely to result from random drift) or not is irrelevant for the purposes of natural selection if it never happens.