Which sense is primarily responsible for balance and spatial orientation?

The sense primarily responsible for balance and spatial orientation is equilibrium. This sense involves the vestibular system located in the inner ear, which detects changes in head position and motion. The vestibular system includes structures like the semicircular canals and the otolith organs, which send signals to the brain about the body's position relative to gravity and acceleration. This information helps maintain balance and stabilizes vision during movement.

Other senses like taste, hearing, and olfaction do not play significant roles in determining balance or spatial orientation. Taste is related to the perception of flavors, hearing pertains to sound detection and interpretation, and olfaction involves the sense of smell. While hearing can contribute to spatial awareness to a degree, it is not the primary sense for balance, making equilibrium the correct answer.