Final answer:
The vestibule is the part of the inner ear that contains the utricle and saccule, playing a crucial role in balance and spatial orientation by detecting linear movements and head positions.
Step-by-step explanation:
The structure that contains the utricle and saccule is the vestibule. The utricle and saccule are components of the inner ear that play a critical role in our sense of balance and spatial orientation. They are responsible for detecting linear accelerations and head positions relative to gravity. Both the utricle and saccule have a similar structure, with hair cells embedded in a gelatinous otolithic membrane that is topped with otoliths, which are particles made of calcium carbonate. When the head moves, the otoliths cause the otolithic membrane to shift, bending the hair cells and sending signals to the brain that enable it to determine head position and movement.
The correct answer to the student's question is D) Vestibule.