Hi nick

I agree. Which fits which? Makes more sense if Life fits the habitat and not the other way around.

As for alternatives there are so many other amino acids, DNA codons, nucleic acids (RNA, TNA, PNA, etc etc) and so forth, some of which are even now powering the next generation of genetic engineering, that our earth's entire biospheric history is but a tiny subset of all possible carbon chemistries compatible with animated complexity.

And that's just carbon - hints of other biochemistries are known, complexity based on sulfur and silicon like nothing yet seen. Plus the prospect of plasma crystal-based "biology". We've barely scratched the surface.