AP BIOLOGY

Detailed explanation-1: -Though bony endoskeletons are the best known, the animal kingdom features three other types of skeleton: exoskeletons, cartilaginous endoskeletons, and hydrostatic skeletons.

Detailed explanation-2: -The skeleton is the internal framework of the body. Bones are probably best known for the hard structural role they play in the human body, but in fact bones are living tissue. Because bone is live tissue it receives nutrients and oxygen from the blood vessels that supply the bone. In addition, bones have nerves.

Detailed explanation-3: -The skeletal system in vertebrates is divided into the axial skeleton (which consists of the skull, vertebral column, and rib cage), and the appendicular skeleton (which consists of the shoulders, limb bones, the pectoral girdle, and the pelvic girdle).

Detailed explanation-4: -The skeleton is subdivided into two major divisions-the axial and appendicular. The axial skeleton forms the vertical, central axis of the body and includes all bones of the head, neck, chest, and back (Figure 7.2).