Skeletons are the internal frameworks of bones that support the bodies of many living organisms, including humans. They provide structure, protect vital organs, and enable movement by serving as attachment points for muscles. In humans, the skeleton consists of 206 bones at adulthood, which can be categorized into the axial skeleton (skull, spine, and rib cage) and the appendicular skeleton (limbs and pelvis). In addition to humans, many animals, such as dogs, cats, and birds, also have skeletons made of bones. Some creatures, like octopuses, have different structures, such as cartilage or exoskeletons, which serve similar functions. Skeletons can vary greatly in size and shape, reflecting the diverse adaptations of species to their environments.