How is it that bone is supposedly stronger than concrete and steel?
Human bones are stronger than concrete because they are made up of a framework of a protein called collagen, with a mineral called calcium phosphate that makes the framework hard and strong. Bones store calcium and release some into the bloodstream when it's needed. [1] Human bones are four times stronger than concrete. [2,3]
Bone is stronger than reinforced concrete and steel because its microarchitecture is complex and built to withstand extreme forces [1]. Bone tissue is a composite of fibrous collagen strands that resemble the steel rebar in concrete and a hardened mineralized matrix that contains large amounts of calcium, just like concrete [1]. But bone outperforms reinforced concrete by several orders of magnitude in compression and tension strength tests [1]. Bones can support loads comparable to that of concrete and steel [2]. Most bone fractures are not caused by compression but by excessive twisting and bending [2].