Final answer:
A skeleton is primarily formed from bone, not from the more flexible cartilage. Bones provide the rigid structure of the body, while cartilage remains at joints and other locations for flexibility and cushioning. The clavicle uniquely develops directly from mesenchymal cells without a cartilage stage.
Step-by-step explanation:
A skeleton formed from bone, not cartilage. Bones are composed of a hard, dense connective tissue that is unlike the softer and more flexible cartilage. Ossification is a process that transforms cartilage into bone tissue during human development.
While cartilage remains in certain areas of the body, such as joints and the rib cage, the majority of the human skeleton is made up of bone, providing a rigid internal framework that supports the weight of the body, allows for movement, and protects internal organs.
The clavicle is unique among the bones of the skeleton because it forms directly from mesenchymal cells through a process called intramembranous ossification, bypassing the cartilage stage entirely. This process makes the clavicle the first bone to begin ossification during embryonic development.
In contrast, the rest of the bones typically develop from cartilage models through a process known as endochondral ossification.