A food chain is a sequence that shows how energy and nutrients flow through an ecosystem. It starts with producers, like plants, which create their own food using sunlight. These producers are then eaten by herbivores, or plant-eating animals, which are in turn consumed by carnivores, or meat-eating animals. Each link in the food chain represents a different level of energy transfer. When an animal dies, decomposers, such as fungi and bacteria, break down its body, returning nutrients to the soil. This process helps sustain the cycle of life within the ecosystem.