Explain the four strokes of a four-stroke internal combustion engine.

The four strokes are: Intake (piston moves down, intake valve opens, air-fuel mixture enters), Compression (piston moves up, valves closed, mixture is compressed), Power/Combustion (spark ignites mixture, expanding gases push piston down), and Exhaust (piston moves up, exhaust valve opens, burnt gases exit). Each cycle takes two crankshaft revolutions to complete, producing one power stroke.