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Newton's Third Law of Motion articulates the principle that forces always occur in pairs. Specifically, it states that for every action, there is an equal and opposite reaction. This means that if an object A exerts a force on object B, then object B exerts an equal force in the opposite direction back on object A. This interaction is fundamental in understanding how objects interact with one another in motion.

This law is essential in a variety of physical situations, such as walking, where the force exerted downward on the ground by our feet is met with an equal force upward from the ground, allowing us to move. It highlights the reciprocal nature of forces, emphasizing that they can never exist in isolation; every force has a corresponding reaction that affects the objects involved.

In contrast, the other options refer to different principles of physics. The first option discusses how the acceleration of an object is influenced by the net force acting on it (which aligns with Newton's Second Law). The third option pertains to the conservation of energy, which is a separate concept not directly related to forces and motion. The fourth choice defines force in terms of mass and acceleration, encapsulating Newton's Second Law rather than his Third Law. Thus, the correct understanding of Newton's Third