Final answer:
A bicycle uses several types of simple machines, including the wheel and axle, for motion, and levers, in the pedals. The gears on a bike can also be understood as a type of screw, another simple machine. However, bicycles do not use pulley systems.
Step-by-step explanation:
A bicycle incorporates several types of simple machines. Firstly, the wheel and axle component of the bike enables motion, where the wheel is the outer circular object and the axle is the rod passing through the center. Secondly, a bicycle also includes levers, for instance, the pedals of the bike act as levers amplifying the force exerted by the rider. Lastly, the types of gears found on many bikes could be seen as a type of screw, considering that the threads of a screw are just a form of inclined plane, which is another simple machine. However, the bicycle does not seem to use a pulley system because there are no ropes involved in a bicycle's mechanism.
Learn more about Simple Machines in a Bicycle