A car's powertrain refers to all the components that generate power and transmit it to the wheels. It includes the engine, transmission, driveshaft, differential, and axles. The engine generates power by burning fuel and air, and the transmission transfers that power to the wheels, allowing the car to move. The driveshaft, differential, and axles work together to transmit power from the transmission to the wheels and to control the car's movement. The powertrain is a critical component of a car, and its performance has a significant impact on the vehicle's speed, acceleration, and overall efficiency.