Which explanation describes the forces involved for a person to walk down the sidewalk?

The person walking down the sidewalk follows the newton's third law of motion.

Explanation:

A person is able to walk down the sidewalk by using the reaction forces from the ground.In simple term, feet pushes the ground and the reaction forces makes the feet able to walk.Another important force included in the walking mechanism is friction. With out friction one cannot walk down the sidewalks.Hence the forces involved in the walking of a person down the sidewalk are:Friction forceAction and reaction force between ground and person's feet.