The correct answer is an axial skeleton.
The axial skeleton is the component of the skeleton, which comprises the bones of the trunk and head of the vertebrae. In the human skeleton, it comprises of six constituents, that is, the ossicles of the middle ear, the skull bone, the hyoid bone, sternum, the rib cage, and the vertebral column.
The axial skeleton in combination with appendicular skeleton forms the whole skeletal system of the human body. The sternum of the breastbone refers to the lengthened flat bone situated in the middle of the chest.
It links with the ribs through cartilage and produces the anterior of the rib cage, therefore, assisting in safeguarding the lungs, heart, and prime blood vessels from injury.