According to Newton's 3rd law, what occurs for every action?

Newton's Third Law of Motion states that for every action, there is an equal and opposite reaction. This means that when one object exerts a force on a second object, the second object exerts a force of equal magnitude but in the opposite direction back on the first object. This fundamental principle of physics highlights the interactions between forces; for every force applied, there's a corresponding force that is equal in size but opposite in direction.

For instance, if you push against a wall, the wall exerts an equal force back against you. This balance of forces is essential in understanding motion and stability in various physical scenarios. In engineering, for example, this principle is crucial for ensuring the design of structures can withstand applied forces without collapsing.

The other options do not accurately represent this law: one doesn't find instances where there is no reaction or an unpredictable reaction to a force according to this law. Furthermore, the concept of a greater reaction does not align with the foundational principles laid out by Newton, which emphasizes the equality and opposition of forces rather than their magnitude difference.