Which of the following best describes an ecosystem's energy flow?

An ecosystem's energy flow is characterized as linear and one way, primarily following a sequence of trophic levels. At the base of this flow are primary producers, such as plants and phytoplankton, which convert solar energy into chemical energy through photosynthesis. The energy then moves to primary consumers (herbivores), which feed on the producers, and subsequently to secondary and tertiary consumers (carnivores and omnivores) as they consume one another.

This progression of energy transfer does not reverse or cycle back; rather, it diminishes with each successive trophic level due to energy loss as heat, metabolic processes, and waste. Therefore, as energy moves through an ecosystem, it follows a one-way trajectory: from producers to various levels of consumers. This linearity underscores the dependence of each trophic level on the one beneath it, illustrating why this description aptly depicts the nature of energy flow in ecosystems.