What defines a food chain?

A food chain is defined as a linear sequence of energy flow from producers to consumers. In this sequence, energy is transferred from one organism to another, starting with autotrophs, such as plants, which convert solar energy into chemical energy through photosynthesis. As primary consumers (herbivores) eat the producers, they obtain this energy, and then secondary consumers (carnivores) consume the herbivores to further transfer the energy up the chain.

This concept emphasizes the direct pathway through which energy moves and highlights the roles of different organisms within an ecosystem. By illustrating the straightforward progression of energy transfer—producers to primary consumers to secondary consumers and so forth—a food chain provides a clear representation of the interactions that sustain life.

While other options discuss broader ecological concepts (like circular energy flow or complex interdependent relationships), they do not specifically capture the essence of a food chain as a simple, linear progression of energy transfer among distinct levels of producers and consumers.