Question

select the example(s) that demonstrate friction acting on an object.
hands rubbing together
an apple growing on a tree
a new shoe rubbing the back of a foot
a rolling ball coming to a stop in tall grass
wheels rolling over a rough road

Explanation:

Friction is a force that opposes the relative motion or tendency of such motion between two surfaces in contact. When hands rub together, there is relative motion between the skin surfaces, creating friction. A new shoe rubbing the back of a foot has relative motion between the shoe and the skin, so friction acts. A rolling ball coming to a stop in tall grass experiences friction between the ball and the grass (opposing its motion). Wheels rolling over a rough road have friction between the wheels and the road surface (due to the roughness, which causes resistance to the rolling motion). An apple growing on a tree has no relative motion (in terms of the concept of friction relevant here - it's just attached, no sliding/opposing motion between surfaces in the context of the force of friction as a resistive force to motion).

Answer:

Hands rubbing together, A new shoe rubbing the back of a foot, A rolling ball coming to a stop in tall grass, Wheels rolling over a rough road.