The law of universal gravitation states that a gravitational force exists between all objects in the universe. This force is directly proportional to the masses of the two objects and inversely proportional to the distance between them. This principle is a law because A. it is contradictory to ideas proposed by other scientists. B. it is subject to change as new technology and evidence emerges. C. it cannot be tested through a controlled scientific investigation. D. it has been demonstrated to be without exception under certain stated conditions.

Answer: D. it has been demonstrated to be without exception under certain stated conditions.

D. It has been demonstrated to be without exception under certain stated conditions.

Explanation:

A principle is simply a proposition based on some results from some experiments. A principle becomes a law when it gains strength. That is when other scientists support and back it.

A scientific law is a statement that describes a natural phenomenon and is not contradicted by repeated experiments over the time.

Sir Isaac Newton's law of gravitation stated "A gravitational force exists between all objects in the universe. This force is directly proportional to the masses of the two objects and inversely proportional to the distance between them."

His law explained that every body in the universe attracts every other body. It explained that it is not just Earth that pulls us towards it. But even sun and moon has their own gravitational pull and so does all other objects. It is just that the Gravitational pull of some objects is negligible.

Newton's law of Gravitation is considered a universal law because it is applicable to almost all the bodies in the universe and is demonstrated to be correct for them under certain conditions.