Well tested, many observations have been made 2. Must be verified by others. Natural processes go towards higher disorder. Entropy is a measure of disorder in the universe. The entropy of the universe is increasing.
Energy is needed to combat entropy.
Matter is neither created nor destroyed during a chemical change. The mass of starting materials equals the mass of products. D. Theories are tentative, there are some facts to support them, but not enough to make a law. E. Models Pictures represent processes that are too small to see. Models are testable, explanatory and tenative.