Final answer:
The simple food chain is represented by Producer → primary consumer → secondary consumer.
Step-by-step explanation:
The correct option that represents a simple food chain is D. Producer → primary consumer → secondary consumer.
In a food chain, energy flows from the producer (plants) to the primary consumer (herbivores) and then to the secondary consumer (carnivores that eat herbivores).
For example, in a grassland ecosystem, grass (producer) is eaten by a grasshopper (primary consumer), which is then eaten by a frog (secondary consumer).
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