Explain how the law of conservation of energy is obeyed in a food chain

Producers are the basis of all food chains because they produce food not only for themselves, but also for all other organisms. When consumers eat producers and other consumers, energy is passed up the food chain. However, with each additional link in the food chain, energy is always lost. According to the law of conservation of energy, though, this "lost” energy does not disappear; it only changes form.

if you mean hydrogen and oxygen then water is the product