The vestibular system's two subsystems include which of the following?

The vestibular system is a crucial part of the inner ear that helps maintain balance and spatial orientation. It consists of two primary subsystems: the semicircular canals and the otolith organs.

The semicircular canals are three fluid-filled structures oriented at right angles to each other, which detect rotational movements of the head. When the head rotates, the fluid within these canals moves, causing the hair cells to bend and send signals to the brain that help us understand our body's position in space.

The otolith organs, which include the utricle and saccule, are responsible for detecting linear acceleration and the effects of gravity. They contain tiny calcium carbonate crystals that shift in response to gravitational forces and linear movements, stimulating hair cells that inform the brain about the head's position relative to gravity.

Together, these two subsystems enable the body to balance and navigate through different types of movement, making this answer the correct one. The other options do not accurately describe the components of the vestibular system, as they include unrelated sensory systems or structures not involved in balance and spatial orientation.