Final answer:
Supercharging increases air-fuel charge density and helps expel exhaust gases, but it does not lower the temperatures of engine components; in fact, it can increase them, requiring additional cooling systems.
Step-by-step explanation:
When discussing the process of supercharging an engine, it’s important to understand what outcomes are generally considered as advantages. Supercharging increases the air-fuel charge density, allowing for more power output from an engine. It also helps in expelling the exhaust gases more effectively. However, the statement that supercharging 'lowers the temperature of the cylinder head, pistons, and valves' is incorrect and therefore does not belong to the list of advantages of supercharging. On the contrary, supercharging, by compressing more air into the cylinder, can increase the heat due to more fuel being burned.
The correct answer is therefore: 'Lowers the temperature of the cylinder head, pistons, and valves'. Supercharging often requires additional cooling systems like intercoolers to mitigate the increased heat from the compressed air.