A hybrid drivetrain combines two power sources: an internal combustion engine and an electric motor. This setup allows vehicles to use both gasoline and electricity, improving fuel efficiency and reducing emissions. The electric motor can assist the engine during acceleration or operate independently at low speeds, making driving more efficient. Hybrid drivetrains come in various configurations, such as series hybrids, where the electric motor drives the wheels, and the engine generates electricity, or parallel hybrids, where both the engine and motor can power the vehicle simultaneously. This technology is commonly found in hybrid vehicles like the Toyota Prius.