sentence2_structure: Pyramid ecosystem<>is used<>to show energy flow through the trophic levels$$$Pyramid ecosystem<>to show<>energy flow
sentence1: 5.2.1 Traces the flow of energy in an ecosystem, noting the dissipation of heat at each energy transfer point and discussing the impact on the ecosystem (e.g., compares biomass and energy at different trophic levels in an ecosystem, and explains why they change;
sentence2: Pyramid ecosystem is used to show energy flow through the trophic levels.
question: What is used to show energy flow through the trophic levels?