Yeah I think the answer is pretty clear why there's one. It was slightly better than the others in some ways like error resistance (important on a young, ie rec

Yeah I think the answer is pretty clear why there's one. It was slightly better than the others in some ways like error resistance (important on a young, ie recently formed, where there's no atmosphere to protect from UV and other comic radiation) and then it just out competed. It's easy to forget just how long it took to go from single celled life (4000 MYA) to multi celled life (~2100 MYA, first fossil evidence at least). That's almost 2 billion years for different versions of DNA/RNA/Amino acids to be tried and tested with almost no chance that we'd find fossil evidence of it. (Not even sure if you could tell from a fossil at all honestly)