You are presented with the question "Biomass is the total mass of organisms at a step in the what?" and the following answer choices: 
- Energy
 - Plants growth
 - food chain
 - agriculture
 - Animal survival
 - Energy.
 - energy usage
 - kinetic energy

Now knowing that biomass is the total mass of organisms at a trophic level and each of the steps in the food chain is a trophic level , choose the best answer.


 

   food chain      