The correct option is (c).
Explanation
This the historical evolution of mechanics, specifically the shift from Aristotelian physics to the classical mechanics of Galileo and Newton regarding the concept of inertia and the natural state of bodies.Statement 1 is Incorrect: Early scientists, particularly Aristotle, believed that the natural state of an earthly object is rest. They argued that a body at rest stays at rest and that a continuous external force is required to keep a body in motion. They did not believe uniform motion was a natural state; they viewed it as a forced state.
Statement 2 is Correct: Galileo Galilei, through his experiments with inclined planes, deduced that objects moving on a frictionless horizontal plane would neither accelerate nor decelerate. He, and subsequently Isaac Newton, established that motion requires no cause (force) to continue if resistive forces like friction are absent. This property is known as inertia.
Statement 3 is Correct: This is a direct articulation of Newton's First Law of Motion. It states that an object remains in its state of rest or of uniform motion in a straight line unless acted upon by an unbalanced external force. Force is the agent of change, not the sustainer of motion.
Key Takeaway: The defining distinction in classical mechanics is that force is not required to maintain motion, but only to change the state of motion (i.e., to produce acceleration).