Which of the following represents energy flow from sunlight to herbivores?

• A. Sunlight → decomposers → plants
• B. Sunlight → plants → herbivores
• C. Plants → sun → herbivores
• D. Herbivores → plants → sunlight

Answer: (B)

Energy flow in ecosystems moves in one direction: sunlight is captured by plants through photosynthesis, storing energy as chemical energy in plant tissues. When herbivores eat those plants, they obtain that stored energy. Some energy is lost as heat at each transfer, so only part of what plants store moves to the next level. This sequence—sunlight to plants to herbivores—best represents the flow of energy from the sun to primary consumers. Patterns that place decomposers between sun and plants or reverse the direction (from herbivores back to plants or to sunlight) don’t reflect how energy moves through trophic levels.