Because, in Essence, That's Really Just a Knick-Knack

Giddy and I were both 100 percent sober, I swear, and having a discussion about broken bones.

A: But why didn't we evolve so our bones are no longer breakable? Wouldn't that make more sense?

G: Well, yeah, but then that would mean our bones would have to be made out of something different. The elements don't change. It's not like you're going to find a lizard made out of gold.