Answer:
When we stand on the floor, we apply a force on the floor surface in the downward direction and in return the floor also exerts an upward and equal force on us.
Step-by-step explanation:
Newton' third law is vey famous and it states that for each and every action, there applies an equal but opposite reaction. Thus the action force and the reaction force always acts on pairs. But they does not contribute to the motion of the object.
One such example that illustrates the action and reaction force from Newton's law is when we stand on the floor we exert a force on the floor surface in downward direction. The floor surface also exerts an opposite and equal force on us in the upward direction.