What is a common application of a bevel gear?

A bevel gear is specifically designed to transmit rotary motion between shafts that are positioned at right angles to each other. This unique feature allows bevel gears to effectively transfer power and motion in mechanical systems where space constraints or specific orientation dictate the need for such an arrangement.

In practical applications, bevel gears are utilized in various machines and devices, such as in automotive differentials or in machine tools, enabling smooth changes in direction of the drive mechanism. Their ability to handle high-speed rotation and transfer motion efficiently makes them ideal for tasks requiring angular shifts in power transmission.

Other options pertain to different mechanical functions. Increasing torque is more characteristic of gear systems, but not specifically bevel gears in isolation. Reducing shaft speed is typically associated with gear reduction arrangements, while providing linear motion aligns more with mechanisms like linear actuators rather than gear systems. Thus, the distinctive role of bevel gears in right-angle power transmission solidifies the correctness of this answer.