A simple model that shows how energy flows through an ecosystem.

A simple model that shows how energy flows through an ecosystem.

• A. Detritovore
• B. Trophic level
• C. Food web
• D. Food chain

Answer: (D)

The main idea is a simple way to picture how energy moves through an ecosystem by following who eats whom in a straight line. A food chain does this best: it shows a linear sequence from producers that capture energy from the sun, to herbivores that eat those producers, to predators that eat the herbivores, and so on. This simple model highlights the direction of energy transfer and the fact that energy diminishes at each step because organisms use much of it for metabolism, growth, and heat. In contrast, a detritivore is just a type of organism that consumes dead matter, not a diagram of energy flow; a trophic level is a position within the chain (producer, primary consumer, etc.), not the model itself; and a food web represents multiple, interconnected feeding relationships, which is more complex than the simple one-way path a food chain provides.

The main idea is a simple way to picture how energy moves through an ecosystem by following who eats whom in a straight line. A food chain does this best: it shows a linear sequence from producers that capture energy from the sun, to herbivores that eat those producers, to predators that eat the herbivores, and so on. This simple model highlights the direction of energy transfer and the fact that energy diminishes at each step because organisms use much of it for metabolism, growth, and heat. In contrast, a detritivore is just a type of organism that consumes dead matter, not a diagram of energy flow; a trophic level is a position within the chain (producer, primary consumer, etc.), not the model itself; and a food web represents multiple, interconnected feeding relationships, which is more complex than the simple one-way path a food chain provides.