The law of motion that describes equal and opposite forces acting as action-reaction pairs is Newton's Third Law of Motion.

Here's a breakdown:

* Newton's Third Law: For every action, there is an equal and opposite reaction.

This means that when one object exerts a force on another object (the action), the second object exerts an equal and opposite force back on the first object (the reaction).

Example:

* When you push a wall, you exert a force on the wall (action). The wall pushes back on you with an equal and opposite force (reaction). This is why you feel resistance when you push against a wall.

Key Points:

* The action and reaction forces always act on different objects.

* The forces are equal in magnitude but opposite in direction.

* The forces occur simultaneously.

Let me know if you have any other questions!