Bones are so hard because of what makes them up – bones are made of organic material (mostly collagen, which is not too hard) and inorganic minerals (which are really hard). Did you know that bone is actually porous (it has lots of little holes all through it)?
Bones 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 by other parts of the body.
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Bones are so hard because of what makes them up – bones are made of organic material (mostly collagen, which is not too hard) and inorganic minerals (which are really hard). Did you know that bone is actually porous (it has lots of little holes all through it)?
Bones 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 by other parts of the body.