The only answer that is not an example of a cell specialization is : <span>Bacteria cells are small in size in order to easily diffuse in and out of the cytoplasm. All of the other examples, the muscle, nerve and the rod and cone cells have specific cell structures, shapes, and proteins that enable them to execute their specific roles in the organism. </span>
Bones of snakes are very loosely fused together like in humans. Hence these bones can move individually allowing the snakes to be really flexible. The ribs of snakes do not join like those of humans but instead, have free ends and do not have a sternum.