a unit used to measure long distances equivalent to the distance from the Sun to Earth is known as the what

What metric units would you use to measure the thickness of a key

Select all of the statements which are true. electrons are located in shells or orbits around the atom. electrons orbit slowly around the atom. electrons travel in one flat path around the nucleus of an atom. the valence of an atom is determined by the number of electrons in the atom's outermost shell.

The fact that the total amount of energy in a system remains constant is a(n)