ATV refers to All Terrain Vehicle. It is also known as three wheeler, four wheeler, quadricycle, quad and quadbike. They are used by single operators. It is designed in such a way that it can handle wider variety of terrain.
The cochlea is the sense organ that translates sound into nerve impulses to be sent to the brain. Each person has two cochlea, one for each ear. The cochlea is a fluid-filled, snail shaped cavern in the mastoid bone of your skull behind each ear. Tiny bones in the middle ear transmit sound from the eardrum across the middle ear and vibrate against the cochlea.
The inner ear structure called the cochlea is a snail-shell like structure divided into three fluid-filled parts.