What is the principle of conservation of energy? A) a possible means to expand our reserves of fossil fuels B) incompatible with the movement of a pendulum C) a law of physics often violated in thermodynamic systems D) a law of physics no known exceptions E) obeyed in chemical reactions, but not in nuclear reactions? What is the answer and why? I'm so confused about energy conservation. I was glad to find this – D) a law of physics, without known exceptions. Energy is neither created nor destroyed.