What is defined as any action on a body that tends to change its size, shape, or state of motion?

The concept described in the question is fundamentally tied to the definition of force in physics. Force is defined as any interaction that, when unopposed, will change the motion of an object. This includes altering an object's size, shape, or state of motion.

For example, when an external force is applied to a solid body, it may change its shape or size through deformation. Similarly, if a force acts on a moving object, it can change its velocity or direction, thus altering its state of motion. This encapsulates the broad definition of force, illustrating its role in affecting physical bodies.

The other choices represent different physical concepts. Displacement refers specifically to the change in position of an object, while acceleration is the rate of change of velocity of an object. Volume, on the other hand, is a measure of the three-dimensional space an object occupies. These terms do not encompass the full spectrum of action on a body as force does.