Read the passage below:
The human skeletal system consists of 206 bones. Our skeleton is made up of two main parts: the axial skeleton and the appendicular skeleton. The axial skeleton includes the skull, spine, rib cage, and sternum, which provide protection for the brain, spinal cord, and vital organs. The appendicular skeleton comprises the upper and lower limbs, shoulders, and pelvis. What is the primary function of the axial skeleton?