A compound machine made of wheels and axles with teeth on the edges of the wheels are known as?

The correct answer is gears. Gears are a type of compound machine that incorporates wheels and axles, specifically featuring teeth along the edges of the wheels. These teeth allow gears to interlock with one another, enabling the transfer of motion and force from one gear to another. This interconnection is crucial for mechanical systems, as gears can change the direction of motion, increase speed, or amplify force, depending on their arrangement and sizes.

The other options do not fit the description. Levers consist of a rigid bar that pivots around a fulcrum to amplify force or motion but do not involve wheels or teeth. Pulleys utilize ropes and wheels to change the direction of force applied but do not feature interlocking teeth. Wedges are inclined planes used to separate or hold objects together, and they do not involve a rotating mechanism like gears do. Each of these other options serves different mechanical purposes, highlighting the distinct nature of gears as a critical component in many machines.