Answer: The 10% rule
Explanation: A trophic level is the position of an organism or group of organisms in a food chain or energy pyramid. The 10% Rule means that when energy is passed on in an ecosystem from one trophic level to the next, only ten percent of the energy will be passed on, this is because at each level, energy is lost directly as metabolic heat, or in other forms such as of waste and dead matter that go to the decomposes and are decayed and broken down to release energy. This means that, majority of the energy that isn't stored is either lost as heat or is used up by the body as it processes the food taken up.