Given a scientific question and its correct answer, generate supporting facts for the answer. This supporting fact can be an explanation for the answer to the given question.
Q: Question: What can demonstrate the decrease in energy, biomass or numbers within an ecosystem? Answer: ecological pyramids
A: 
Ecological pyramids can demonstrate the decrease in energy, biomass or numbers within an ecosystem. Energy pyramids are discussed at http://www. youtube. com/watch?v=8T2nEMzk6_E (1:44).