Which law is known as the law of action-reaction

The law that relates action to reaction is the Newton's third law of motion.

Explanation:

Newton's third law of motion states that for every action there is an equal and opposite reaction.

Action-reaction force pairs make it possible for fishes to swim, birds to fly, cars to move etc,

Furthermore, take for example, While driving down the road, a firefly strikes the windshield of a car (Action) and makes a quite obvious mess in front of the face of the driver (Reaction) i.e The firefly hit the car and the car hits the firefly.

The statement above means that in every interaction, there is a pair of forces acting on the two interacting objects in this case, the car and fly. The size of the force on the car equals the size of the force on the fly. These two forces are called action and reaction forces and are the subject of Newton's third law of motion.