The food chain is a linear sequence of organisms where nutrients and energy are transferred from one organism to another as they are consumed. It begins with producer organisms like plants, then primary and secondary consumers that eat the producers, and ends with decomposer organisms like bacteria that break down waste. A food chain explains the feeding relationships between organisms at different trophic levels in an ecosystem. Multiple interconnected food chains form a more complex food web that better represents the flow of energy and interactions between species in an environment.