What does Newton's third law of motion state?

Newton's third law of motion states that for every action, there is an equal and opposite reaction. This principle highlights the interactions between two bodies. When one body exerts a force on a second body, the second body exerts an equal force in the opposite direction on the first body. This means that forces always occur in pairs; they are mutual interactions that maintain equilibrium.

This concept is crucial for understanding how motion works in the physical world, as it explains the dynamics of interactions, such as why a swimmer pushes against the water to propel themselves forward, and in response, the water pushes back with equal force, propelling the swimmer ahead. This law underscores the conservation of momentum in collisions and various movements in nature and man-made systems.

The other statements refer to different laws or principles, such as those related to force, inertia, or conservation of energy, but they do not encapsulate the essence of Newton's third law.