How does energy flow differ from nutrient cycling in ecosystems?

How does energy flow differ from nutrient cycling in ecosystems?

• A. Nutrients cycle repeatedly within the ecosystem, while energy flows through trophic levels and is dissipated as heat.
• B. Energy cycles; nutrients flow in one direction only.
• C. Energy and nutrients both cycle and are stored in biomass.
• D. Both energy and nutrients are stored indefinitely in organisms.

Answer: (C)

Energy and nutrients move through ecosystems in different ways. Energy enters as sunlight and is captured by producers, then passes through the food web from producers to herbivores to predators. With each transfer, some energy is lost as heat, so energy moves in a one-way stream and gradually diminishes; it does not return to be reused in the same form.

Nutrients—elements like carbon and nitrogen—cycle continuously. They are taken up by organisms, returned to the environment through waste and decomposition, and become available again for use by others. This recycling keeps nutrients in circulation, accessible for new growth and metabolism.

So, the best description is that nutrients cycle repeatedly within the ecosystem, while energy flows through trophic levels and is dissipated as heat. While biomass can store chemical energy for a time, energy isn’t stored indefinitely or recycled like nutrients. The idea that energy cycles or that both are stored indefinitely in organisms doesn’t fit how ecosystems actually work.