How does a clutch function in a manual transmission?

The function of a clutch in a manual transmission is primarily to disengage the engine from the transmission. This disengagement allows the driver to shift gears without damaging the transmission or stalling the engine. When the clutch pedal is pressed, the clutch disc is separated from the flywheel, interrupting the power transfer from the engine to the transmission. This makes it possible to smoothly change gears and match the engine speed with the wheels, ensuring a seamless driving experience.

The other choices do not accurately describe the role of the clutch. For instance, the clutch does not increase engine power; its function revolves around managing the connection between the engine and the transmission. Additionally, while the clutch indirectly facilitates the connection between the gearbox and the wheels by allowing gear changes, its primary function is not to connect but rather to disengage the engine from the transmission. Lastly, regulating engine temperature is unrelated to the clutch's purpose and is managed by the vehicle's cooling system instead.