Answer – According to the theory known as the law of energy conservation, energy can neither be created nor destroyed; only it can transform from one form of energy into another form. Toy cars that roll down ramps are an excellent example of the transfer of potential energy to kinetic energy.
According to the law of conservation of mass in a chemical reaction, mass is neither created nor destroyed. There are many examples of this. Carbon dioxide, for example, forms when coal is burned. In this case, the mass of the carbon atom does not change even though it is now gas.