Which two main groups make up the human skeleton?

The human skeleton is primarily divided into two main groups: the axial skeleton and the appendicular skeleton.

The axial skeleton comprises the bones that form the central axis of the body, including the skull, vertebral column (spine), and rib cage. This group supports and protects the organs of the head, neck, and trunk.

On the other hand, the appendicular skeleton involves the bones of the limbs and the girdles (pectoral and pelvic) that attach them to the axial skeleton. It includes the shoulder bones, the bones of the arms and hands, the pelvic bones, and the bones of the legs and feet. This division is critical for movement and interaction with the environment.

The other options present groupings that either do not encompass the full range of the skeleton or inaccurately pair categories. For instance, the pelvic skeleton is part of the appendicular skeleton, while cranial bones are included in the axial skeleton. Moreover, the term "longitudinal skeleton" is not a recognized term in anatomical divisions. Thus, identifying the correct division of the skeleton into axial and appendicular bones is essential for understanding human anatomy and its organization.