Final answer:
The coiled, snail-shaped, fluid-filled structure in the ear is the cochlea, which is essential for converting sound waves into neural signals for the brain.
Step-by-step explanation:
The coiled, snail-shaped, fluid-filled structure found in the ear is called the cochlea. It plays a critical role in the process of hearing by translating the pressure waves generated at the oval window into neural signals. These waves travel through the perilymph fluid in the cochlea, stimulating nerves at the base of the organ of Corti, which contains hair cells that convert the mechanical movement into electrical signals which are then sent to the brain via the auditory nerve.