Second, the difference:
Firstly, the essential problems of the two concepts are different. Action and reaction describe the law of action between two objects. A has a strong effect on B, and B must also have a strong effect on A; Two-force balance describes the two-force characteristics of an object in equilibrium under the action of two forces.
Secondly, the two forces of action and reaction are of the same nature, either gravity, elasticity or friction, etc. However, the balance of two forces is not the case. As long as the two forces act on the same object with equal magnitude and opposite directions and act on the same straight line, it is the balance force, regardless of the nature of the two forces.
Re-acting force and reaction force are simultaneous, producing at the same time, changing at the same time and disappearing at the same time; The balance of two forces does not have this characteristic.