Food Chain is defined as a flow of energy in the form of food from one organism to another. The flow of energy follows the law of \(10\)% energy transfer from every organism which is rather considered as trophic levels. The \(10\)% energy transfer states that at each trophic level only \(10\)% of the energy is transferred to the next trophic level. For example, you can take grass, a deer and a lion which constitutes the most simple food chain having only 3 trophic levels as the number of organisms is equal to the number of trophic levels. The energy released from the sun is absorbed by the grass (producers - First trophic level) , \(10\)% of energy is transferred from grass to deer (primary consumer - Second trophic level) and from deer to lion (secondary consumer - Third trophic level).