Sharks may have some short ribs, but the ribs don't form a protective cage around the internal organs as they do in most other fishes. A shark's skin is embedded with millions of tiny, sharp, toothlike scales, giving it a texture like sandpaper.
Most sharks do.
The tongue is formed by a heavy fold of tissue from the floor of the mouth, supported internally by cartilage. The special alignment and grooved structure of the toothlike scales embedded in a shark's skin work to decrease drag, thereby greatly increasing swimming proficiency. This arrangement is so effective that scientists are experimenting with sharklike skin surfaces for airplanes and boat hulls. True for most sharks, but not all. Some can pump water over their gills by opening and closing their mouths, even when resting on the bottom.