What sensory organs do sharks have that allows them to detect movement in the ocean?

Sharks have a unique sensory organ called the ampullae of Lorenzini, which allows them to detect movement in the ocean. These ampullae are filled with a jelly-like substance and are located on the shark's head, around the eyes, nostrils, and mouth. When water moves, it causes the jelly in the ampullae to move, which stimulates the sensory cells located inside. These sensory cells then send signals to the shark's brain, which can detect the direction and strength of the water movement. This allows sharks to detect the movement of prey, predators, and other objects in the water, even in complete darkness.