Which statement best summarizes the law of conservation of energy
a) when work is done, energy is lost.
b) heat flows from a warm body to a cold body.
c) if energy disappears in one form, it must reappear in another.
d) the fewer the number of valence electrons, the better the insulator

Option (C) is the correct answer.

Explanation:

According to law of conservation of mass, energy can neither be created nor it can be destroyed as it can only be transformed from one form to another.

For example, when ice melts at room temperature then it absorbs heat from its surroundings and converts into liquid state of water.

So, the heat energy absorbed by ice is used in breaking of bonds between ice particles that results in liquid form. Hence, energy from solid state disappears and it reappears in liquid form.

Thus, we can conclude that the statement, if energy disappears in one form, it must reappear in another, best summarizes the law of conservation of energy.