Bones are made of two main materials: calcium salts make bones hard, and collagen fibers make them strong but also a bit flexible. After death the collagen rots away, leaving just the durable hard parts behind. In life, the bones of a person's skeleton support the body and protect its internal organs.
Because bones endure after death, skeletons - and the skull and crossbones - have for centuries been symbols of disease, danger, and death.
Your "funny bone" isn't a bone at all; it's a spot on the outer bit of your elbow that, if you hit or knock it, gives you a weird tingly pain. This is because the ulnar nerve crosses the bone at that point.
Human and giraffes have the same number of neck bones, or cervical vertebrae. They both have seven, although each of the giraffe's vertebrae are much longer!
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