In the context of energy flow through ecosystems, what happens to energy as it moves from primary producers to higher trophic levels?

• A. Energy is recycled indefinitely within the ecosystem because decomposers convert it back into usable energy for producers.
• B. All energy is conserved and transferred with nearly 100% efficiency from one trophic level to the next.
• C. Most energy is lost as heat at each trophic transfer due to metabolism, so less energy is available at higher trophic levels.
• D. Energy increases at each successive trophic level because organisms concentrate energy as biomass accumulates.

Answer: (C)