What best describes a food chain?

A food chain is best described as a linear sequence that illustrates the flow of energy and nutrients through different organisms in an ecosystem. It starts with a primary producer, typically a plant, which captures solar energy through photosynthesis. This energy is then transferred to primary consumers, such as herbivores, that eat the producers. From there, energy is passed to secondary and tertiary consumers, or carnivores, that eat the primary consumers. Each step in this sequence shows how energy moves from one trophic level to the next, highlighting the direct feeding relationships among species.

While the other options touch on aspects related to ecology, they do not specifically define a food chain. For instance, a complex network of interrelated food webs suggests a more intricate relationship than the straightforward flow depicted in a food chain. Similarly, an illustration of trophic levels and species interactions encompasses broader ecological dynamics and interactions, rather than the specific linear flow of a food chain. Lastly, a map of dietary habits provides insights into feeding behaviors without capturing the direct energetic connections represented in a food chain. Thus, defining a food chain as a linear sequence of energy flow encapsulates its fundamental characteristic most accurately.