What is the Third law of motion?

Newton's Third Law of motion states that every action has an equal and opposite reaction. This essentially states that if you exert a force on something, that object will exert the same force on you in the opposite direction. An example of this is you sitting at your computer now. Your weight is a force pushing down on your chair, and the chair is pushing up on you with the same force as your weight. This keeps you in one place.