What is the primary function of the axial skeleton?

The primary function of the axial skeleton is to provide support to the appendicular skeleton. The axial skeleton comprises the skull, vertebral column, and rib cage, forming the central axis of the body. This structure supports the weight of the body and provides a framework for muscle attachment, allowing for proper function and stability of the appendicular skeleton, which includes the limbs and girdles. This support is crucial because it maintains posture, balances the body, and aids in movement by allowing the limbs to function effectively in coordination with the axial structure.

While the other options may relate to functions of bones or other parts of the skeletal system, they do not represent the primary role of the axial skeleton. For instance, although the axial skeleton does help protect internal organs like the brain and thoracic cavity, this function is secondary to its primary role in providing support. Similarly, it does not facilitate limb movement directly, nor is it primarily responsible for the production of blood cells, which occurs primarily in the bone marrow of long bones within the appendicular skeleton. Thus, the correct understanding of the axial skeleton's function emphasizes its supportive role in the human body.