Final answer:
About 10% of the energy at one trophic level is passed on to the next level in a food chain, with the rest being used for metabolism or lost as heat.
Step-by-step explanation:
The percentage of energy available to be passed on to the next organism in a food chain is approximately 10%. When energy is transferred from one trophic level to the next, 90% is used by the organisms for metabolic processes or is lost as heat.
Only the remaining 10% is stored and passed on to organisms at the next higher trophic level. This explains why food chains are typically short, usually not exceeding four trophic levels due to the insufficient energy that would remain for additional levels.