Every time energy is transferred between organisms in a food web, some of the energy is lost as heat

In every level of the food chain is lost the 90 % of energy.

Explanation:

That means that the total energy taken from the sun, the 10 %  is lost in the next step ( the primary consumers) and just the 1% pass to the second consumers, and just the 0.1 % pass to the third consumers. The 90 % of energy that is lost between one level and the second, the living thing uses to their movements, the metabolism, etc.

carbon atoms, hydrogen, oxygen, and nitrogen.