What is a food chain?

A food chain is defined as a linear sequence of organisms through which nutrients and energy are transferred from one to another. This sequence begins with producers, such as plants, that convert sunlight into energy through photosynthesis. The energy stored in these producers is then passed on to primary consumers (herbivores) that eat the plants, followed by secondary consumers (carnivores or omnivores) that consume the herbivores, and so on. Each step in this sequence is known as a trophic level, highlighting how energy flows from one level to the next in a straightforward manner.

The other options do not accurately capture the definition of a food chain. For instance, while an ecosystem's energy store suggests a broader concept of energy storage within an ecosystem including all forms of reserves, it does not specify the transfer process that defines a food chain. Similarly, the idea of a cycle of nutrient destruction suggests a negative ecological interaction, which contrasts with the constructive energy flow represented by a food chain. Lastly, a web of plant relationships would imply a more complex network of interactions (a food web) rather than the linear transfer of energy that a food chain describes. Thus, the option that focuses on a linear sequence of organisms aligns perfectly with the defined