[Restorer]

Not me, unfortunately.

The evolutionary explanation is that all lifeforms use the same building blocks because they're all descended from the first life form to develop them.

The creationist explanation is that God doesn't fix things that aren't broken.

[newgeezer]

Another "creationist explanation" says perhaps one is assuming too much about DNA & RNA when one assumes all the answers are contained in the DNA & RNA.

In other words, DNA & RNA may be no more the end-all "building blocks" than is the lowly carbon element.

Just a thought.