You are presented with the question "What is fourty percent of the total mass of organisms at a trophic level?" and the following answer choices: 
- Energy.
 - carbon
 - pan
 - glucose
 - matter
 - Energy
 - fungi
 - food

Now knowing that biomass is the total mass of organisms at a trophic level and fourty percent of biomass is carbon, choose the best answer.


 

  carbon       