Consider a person applying a horizontal force to a refrigerator on a level floor. Although they are pushing, there is enough friction that the refrigerator does not move. Check all of the following that would be interaction pair forces (Newton's Third Law Pairs) in this situation. downward gravitational force on refrigerator by the earth --- upward normal force on refrigerator by floor normal force on refrigerator by person frictional force on refrigerator by floor normal force on refrigerator by person -- normal force on person by refrigerator friction force on refrigerator by floor -- friction force on floor by refrigerator