What machine is described as consisting of a wheel attached to an axle?

A machine consisting of a wheel attached to an axle is known as a wheel and axle. This design allows for the efficient movement and transfer of force, making it easier to lift or move loads. The wheel rotates around the axle, and when force is applied to one, the other moves in a coordinated manner. This structure is commonly found in various applications, such as in cars, bicycles, and various types of machinery, where the wheel simplifies movement without adding excessive friction.

The other options do not fit the description as clearly. A lever involves a rigid bar that pivots around a fixed point, a pulley consists of a rope or belt that goes over a wheel, and an inclined plane is a flat surface tilted at an angle. None of these include both a wheel and an axle as their primary components.