As per ten per cent law, in an escosvstem, all energy is provided by sun though photosynthesis. All of the energy stored by the auttftrophs in the form of food is available to the herbivores as food. Herbivores can stored only 10% of this energy in their biomass and 90% is used in life activities. In the same way, herbivores are eaten by carnivores and carnivores by top carnivores. Thus/only 10% of energy is captured by the organisms of next higher trophic level.