Biology
Bone Structure
Quick fact
Bone is a living tissue that constantly remodels itself; about 10% of your total bone mass is replaced each year through the work of bone-building and bone-resorbing cells.
Why this is interesting
You probably know bones are hard, but did you realize they're actually a clever composite of a dense outer shell and a lightweight inner scaffold—like a skyscraper built with steel beams and foam filler?