Which structure is responsible for maintaining equilibrium in the body?

The labyrinth is the correct answer because it is a complex structure located in the inner ear that plays a crucial role in maintaining balance and equilibrium in the body. It consists of two parts: the bony labyrinth and the membranous labyrinth, which house the vestibular system. The vestibular system includes semicircular canals and otolith organs that detect changes in head position and motion. This information is then sent to the brain, helping the body understand its orientation in space and maintain balance.

The auditory canal primarily serves as a passage for sound waves to travel to the eardrum, and while the Eustachian tube is essential for equalizing pressure in the ear, it does not directly relate to balance. The cochlea, on the other hand, is involved in the sense of hearing, converting sound vibrations into nerve signals, rather than in maintaining equilibrium.