Which structure is known for its role in hearing as it contains the receptor for sound?

The cochlea is the correct choice because it is a crucial structure in the inner ear responsible for hearing. Inside the cochlea, there are specialized sensory cells known as hair cells, which have tiny hair-like projections called cilia. These hair cells act as receptors that pick up sound vibrations and convert them into electrical signals that are transmitted to the brain via the auditory nerve. This process is essential for our ability to perceive sound.

In contrast, while cilia are involved in the cochlea's function as part of the hair cells, they do not independently serve as the main hearing structure. The coccyx, often referred to as the tailbone, has no role in hearing and pertains to the human skeletal system. The cornea is a part of the eye and is primarily involved in vision rather than hearing. Each of the other structures is associated with different functions within the body, emphasizing the unique role of the cochlea in the auditory system.