Answer: femur
Explanation:
A rib cage can be define as the combination of the ribs that are attached to the vertebral column and sternum bone in the front. This bony cage protects the heart and lungs which are the internal vital organs from injury.
Femur is the thighbone. It is the upper bone of the lower limb. The head of the bone femur forms a ball and socket arrangement with that of the hip bone specifically with the acetabulum of the pelvis.
On the basis of the above explanation, femur bone does not belong in the list of the given bones.
