Final answer:
A Class II lever increases the size of the applied force by allowing a smaller input force to exert a larger output force by placing the input closer to the load than the fulcrum.
Step-by-step explanation:
The simple machine that actually increases the size of the applied force is a Class II lever. A Class II lever works in a way that the input force is applied closer to the load than to the fulcrum, which allows for a large output force to be exerted on the load with relatively smaller input force. This is why when force is applied near the fulcrum over a shorter distance, a Class II lever can lift a heavy object more easily compared to other simple machines.