It isn't easy to become a fossil. ... Only about one bone in...

It isn't easy to become a fossil. ... Only about one bone in a billion, it is thought, becomes fossilized. If that is so, it means that the complete fossil legacy of all the Americans alive today - that's 270 million people with 206 bones each - will only be about 50 bones, one-quarter of a complete skeleton. That's not to say, of course, that any of these bones will ever actually be found.