Concept:Body balance in humans depends on sensory receptors in the inner ear that detect head movements and posture.
Explanation:The semi-circular canals are three fluid-filled, looped structures located within the inner ear.
Each canal is oriented in a different plane and contains hair cells surrounded by fluid.
When the head rotates or moves, the fluid within the canals shifts and bends these hair cells.
The hair cells then generate nerve impulses that travel to the brain, giving information about rotational balance and spatial orientation.
If these canals are defective, the brain cannot accurately sense changes in head position, resulting in poor body balance.
Therefore, inability to maintain balance is most likely due to damage or defect in the semi-circular canals.
Answer:C. Semi-circular canals