A) A 4-stroke engine has a 4-step process.

1. Intake: When the intake valve opens. Fuel is drawn in on the down stroke.

2. Compression: When the piston moves upwards. The fuel is compressed.

3. Power: After the fuel is compressed. An ignition occurs to create engine power.

4. Exhaust: The exhaust valve opens. And the exhaust gases will leave the cylinder.

B) A 2-stroke engine has a 2-step process.

1. Stroke (ignition/compression): The piston will rise. Air and fuel enter the crankcase. The fuel and air mixture is compressed and ignited.

2. Downstroke (power/exhaust): When the fuel is ignited. The piston is pressed down. and exhaust gases are expelled.

4-stroke engines are more fuel-efficient and environmentally friendly. Meanwhile, 2-stroke engines use fewer moving parts for easier maintenance.