What is a food chain?

• A. A sequence showing who eats whom in an ecosystem.
• B. A chain of food storage in animals.
• C. A method of energy production in plants.
• D. A diagram of the water cycle.

Answer: (A)

Energy moves through ecosystems as organisms feed on one another. A food chain is a simple sequence that shows which organisms eat which, starting with a producer that makes its own food, then primary consumers that eat producers, and higher-level consumers that eat those organisms. This shows how energy is passed from one organism to the next at different levels. For example, grass is eaten by a rabbit, which is eaten by a fox. In real life, many chains are connected into a web because organisms often have more than one food source.

The other options don’t describe feeding relationships or energy transfer. One talks about storing food in animals, another about how plants produce energy, and the last is the water cycle.