Final answer:
The clavicle, or collarbone, is the only option that is not part of the axial skeleton. The occipital bone, vertebra, and ribs are all part of the axial skeleton, which consists of the skull, vertebral column, and thoracic cage (rib cage). The clavicle is part of the appendicular skeleton, connected to the axial skeleton via the pectoral girdle.
Step-by-step explanation:
The question asks which of the following is not a bone of the axial skeleton. The axial skeleton forms the central axis of the body and includes the bones of the skull, ossicles of the middle ear, hyoid bone of the throat, vertebral column, and the thoracic cage (rib cage). The choices provided are a. Occipital, b. Vertebra, c. Rib, and d. Clavicle.
The occipital bone, vertebra, and rib are all part of the axial skeleton. The occipital bone is part of the skull, the vertebra makes up the vertebral column, and the ribs are part of the thoracic cage.
The clavicle (or collarbone), however, is not part of the axial skeleton. Instead, it is part of the appendicular skeleton, which includes the bones of the appendages (arms and legs), as well as the bones that connect these to the axial skeleton (the pectoral and pelvic girdles). The clavicle specifically forms part of the pectoral girdle that connects the upper limb to the body trunk. Therefore, the answer to the question is d. Clavicle.
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