The size of a food chain can vary, but the number of levels that a food chain can reach is limited. Why does this limit exist?

Only some of the energy at one trophic level is passed on to the next; much is used by organisms or lost as heat and waste. As energy decreases at each step, eventually there is not enough to support another level. This is why energy loss limits food-chain length, making “Energy is lost at each trophic level” correct.

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