An ecological study of a grassland ecosystem measures the energy flow through a population of grasshoppers (primary consumers). The grasshoppers ingest grass containing 2.40×106 kJ m−2 yr−12.40 \times 10^6 \text{ kJ m}^{-2} \text{ yr}^{-1}2.40×106 kJ m−2 yr−1 of energy. They lose 1.08×106 kJ m−2 yr−11.08 \times 10^6 \text{ kJ m}^{-2} \text{ yr}^{-1}1.08×106 kJ m−2 yr−1 in faeces and excretion, and lose 9.60×105 kJ m−2 yr−19.60 \times 10^5 \text{ kJ m}^{-2} \text{ yr}^{-1}9.60×105 kJ m−2 yr−1 through respiration.
What percentage of the energy ingested by the grasshoppers is converted into biomass available for transfer to the next trophic level (secondary consumers)?
15%15\%15%
40%40\%40%
45%45\%45%
60%60\%60%