Answer;
Approximately 0.1 or 10 percent of the energy.
When the energy flow through an ecosystem is measured at each trophic level, approximately 0.1 of the available energy passes from one level to the next.
Explanation;
Energy decreases as it moves up trophic levels because energy is lost as metabolic heat when the organisms from one trophic level are consumed by organisms from the next level.
As little as 10 percent of the energy at any trophic level is transferred to the next level; the rest is lost largely through metabolic processes as heat