The correct answer is: 3; 2; 1.
- A class 3 lever (like a tweezers) never has a mechanical advantage because the effort is applied between the load and the fulcrum.
- A class 2 lever (like a wheelbarrow) always has a mechanical advantage because the load is between the effort and the fulcrum.
- A class 1 lever (like a seesaw) could go either way, depending on the positions of the load, effort, and fulcrum.