How do air brakes differ from hydraulic brakes?

Answer: C — Air brakes use compressed air, while hydraulic brakes use fluid pressure.

Air brakes operate using compressed air, which is essential for their function. When the brake pedal is pressed, air is released from a reservoir, leading to the application of the brakes through air pressure. This system can generate substantial stopping power without needing an extensive hydraulic system. In contrast, hydraulic brakes rely on the principle of liquid pressure. When you press the brake pedal, it pushes brake fluid through a network of lines, transferring force to each wheel's braking mechanism. This fundamental difference in how force is applied is a key distinguishing feature between the two braking systems. While air brakes typically require less maintenance due to fewer moving parts and a simpler design, that is not the defining characteristic that distinguishes them from hydraulic systems. Additionally, the effectiveness of air brakes in snowy conditions versus hydraulic brakes does not define their operational difference; both can perform adequately under certain conditions, depending on design and usage context. Thus, the primary distinction lies in the medium through which the braking force is generated and applied.