Final answer:
The roughest surface exhibits the most friction due to the microscopic peaks and valleys that create resistance against motion. Lubrication improves efficiency by reducing this friction.
Step-by-step explanation:
The surface with the most friction is Option 2: The surface with a rough texture. Friction occurs due to the interactions at the microscopic level between two surfaces. If you look closely at surfaces that create friction, you will observe that they are rough, even if they appear smooth to the eye. When an object like a crate is pushed, and it begins to move, it does so by overcoming the tiny peaks and valleys of the surface's roughness. The degree of roughness, which contributes to higher friction, makes it necessary to apply more force to initiate motion, especially if the surfaces are pressed harder together, as would be the case if another box were placed on the crate.
Lubrication can drastically increase the efficiency of a simple machine by reducing friction. This is because lubricants fill the gaps of the rough surface, creating a smoother layer that reduces the amount of force needed for motion. Thus, with lubrication, surfaces can move past each other with less resistance and higher efficiency.