1. The problem asks to identify the forces that represent the action-reaction pair during a collision. 2. According to Newton's Third Law of Motion, for every action, there is an equal and opposite reaction. 3. This means the forces involved in a collision are equal in magnitude but opposite in direction. 4. The action force is the force exerted by the first object on the second object. 5. The reaction force is the force exerted by the second object back on the first object. 6. These two forces form the action-reaction pair during the collision.