Question

mention two movement differences between shark and other fish.

Answer 1

Most bony fish have a special swim bladderthat helps them move around in the water. When the fish takes in oxygen, it can release some of the gas into the bladder. This increases the fish's buoyancy, so it rises through the water. To sink down to the bottom, the fish squeezes some of the gas out of the bladder, decreasing its buoyancy. In this way, a fish is something like a blimp or hot air balloon that uses the upward lift of atmospheric buoyancy to change altitude.

A shark is more like an airplane. It doesn't have a swim bladder, so it uses its forward movement to control vertical position. The tail is like the shark's propeller -- the shark swings it back and forth to move forward. In an airplane, this forward movement pushes air around the wings. In a shark, this forward movement pushes water around the fins. In both cases, this movement of matter creates lift -- the fluid is different, but the principle is exactly the same.