Which scientific law explains that nothing in nature starts or stops moving without an outside force?

Newton's First Law of Motion, also known as the law of inertia, states that an object at rest will remain at rest, and an object in motion will continue in motion at a constant velocity unless acted upon by a net external force. This principle highlights the inherent tendency of objects to resist changes in their state of motion. It underscores the idea that motion does not occur spontaneously; instead, an outside force is required to initiate or alter an object's movement.

This concept is fundamental in understanding how forces interact with objects, as it lays the groundwork for the subsequent laws of motion proposed by Newton, which further explore the relationship between force, mass, and acceleration, as well as the reciprocal nature of forces acting on objects. In contrast, the other options address different aspects of motion and forces. For instance, Newton's Second Law deals with the relationship between force, mass, and acceleration, while the Third Law discusses action-reaction pairs. The Law of Conservation of Energy pertains to the transformation of energy rather than motion specifically, making Newton's First Law the most applicable for explaining the effects of external forces on motion.