Correct Response: B. As energy flows from lower to higher trophic levels, only about 10% of it is transferred from one level to the next; the rest of the energy is lost to the environment. Energy is required to sustain biomass, so higher trophic levels contain less biomass because there is less available energy than at lower trophic levels. Biodiversity may be lower (A) at the higher trophic levels, but limited biodiversity is also likely a result of less available energy at these levels. Decomposers (C) can be found at all trophic levels as they clean up and return all dead organisms to organic matter; however, decomposers do not make up a large amount of the biomass. At higher trophic levels, toxic compounds (D) accumulate through biomagnification, but this does not significantly decrease the amount of biomass at the higher trophic levels.