Question

The sense of equilibrium is determined by
A. Basilar membrane of cochlea
B. Tectorial membrane of cochlea
C. Sensory crista of ampulla
D. Sensory cells of organ of Corti

Answer 1

Hint: Crista structures which are projecting ridges contain hair cells having sensory receptors present in the ear. Sense of equilibrium is the spatial arrangement or structure that helps humans and animals from falling when they are in movement or standing at any position.

Complete answer:
When we talk about a sense of equilibrium it means we are talking about the balances or spatial arrangement such that the particular organism does not fall when he/she tries to balance on small paths or when he/she is standing or moving.
Equilibrioception is the result of many sensory systems involvement together that is, eyes, ears and other body systems. The balance system works with the visual and skeletal system which works with the eye and brain system to maintain the proper balance. These all skills can be acquired with practice and proper guiding.
Our ear consists of many parts which involve this balancing technique. Ampulla is the organ which is a sac-like structure which is a canal or duct like organ. It's one of the ends is a semicircular canal with the three semi-circular and connected internally tubes present in the inner parts of the ear.
This structure is a part of a bony labyrinth which has an endolymph fluid. Also have a projecting ridge called crista ampullaris. These contain hair-like sensory cells or sensory receptors having cytoplasmic projections celled stereocilia. These stereocilia have specific receptors which help in sensing movements of the body and movements of relative things.

So, we can conclude that Sensory receptors or crista of the ampulla helps in the sense of equilibrium of animals or humans.

Note: Other parts of the ear help the sensing receptors present in the ear but they do not participate in the sensing movement or equilibrium. Sensory cells of the organ of Corti helps in the transduction of auditory signals that are sound waves. Thus, we do not consider this option as the correct option.