Final answer:
Energy in most terrestrial and near-surface marine ecosystems flows from producers to consumers and then to decomposers, creating a one-way system as depicted in food chains and food webs.
Step-by-step explanation:
The question relates to the flow of energy in ecosystems, specifically terrestrial and near-surface marine ecosystems. The correct description of energy flow is: Energy flows from producers to consumers to decomposers. In an ecosystem, energy enters as sunlight, which is harnessed by producers like plants via photosynthesis to create their own food. Consumers, such as herbivores, obtain their energy by feeding on these plants, and then carnivores gain their energy by consuming herbivores. Finally, decomposers break down the organic matter left by both producers and consumers, recycling nutrients back into the ecosystem, but they do not redirect energy back to producers or consumers. The law of thermodynamics dictates that as energy transfers from one level to the next, a substantial amount is lost as heat, emphasizing a one-way flow of energy.