Which of these machines reduces friction when lifting or moving objects?

The correct answer is that all of the machines listed reduce friction when lifting or moving objects, each in its unique way.

A pulley simplifies the process of lifting by allowing a person to pull down on a rope, which subsequently raises the load. This system can change the direction of the force applied, and using multiple pulleys can reduce the amount of effort needed to lift heavy objects, effectively minimizing the friction involved in lifting.

A wedge functions by converting a force applied to its blunt end into forces perpendicular to its inclined surfaces. This reduces the friction between the wedge and the surface of the object being moved, allowing it to be separated or lifted more easily. The shape of the wedge helps to distribute the force efficiently, further minimizing resistance.

A wheel and axle system facilitates the movement of heavy objects by reducing the surface area in contact with the ground. As the wheel rolls, it decreases the friction that would otherwise be present if the object were dragged. This allows objects to be moved with much less effort, which is why wheels are widely used in various applications.

Since all three options actively participate in reducing friction and improving the efficiency of lifting or moving objects, the inclusion of all these devices in the answer is valid and highlights the various methods used to achieve this