Question

which simple machine would make it easier to push a wheelchair onto a bus?
lever
inclined plane
pulley
screw

Explanation:

An inclined plane reduces the effort needed to lift an object (like a wheelchair onto a bus) by increasing the distance over which the force is applied. A lever is for pivoting around a fulcrum, a pulley changes the direction of force (usually for lifting with ropes), and a screw is for converting rotational motion to linear motion (like in a jack). Since we want to push the wheelchair up (a linear motion over a sloped surface), the inclined plane is the right choice.

Answer:

inclined plane