How is energy primarily transferred in an ecosystem?

Energy is primarily transferred in an ecosystem through food chains and trophic levels, which illustrate the flow of energy from one organism to another within a community. In an ecosystem, energy begins with primary producers, typically plants, that convert sunlight into chemical energy through photosynthesis. This energy then moves through various trophic levels as herbivores consume these plants, and subsequently, carnivores feed on the herbivores.

Food chains depict these relationships in a straightforward manner, while food webs show the complex interconnections between different organisms. Each step in these chains or webs reflects a transfer of energy, illustrating how energy flows from producers to consumers and eventually to decomposers, which play a crucial role in recycling nutrients back into the ecosystem.

Other options do not fully capture the primary mechanism of energy transfer in ecosystems. While photosynthesis is vital for energy production, it is just one part of the larger process. Chemical reactions in the soil and abiotic factors like sunlight and water contribute to the ecosystem's functioning but do not encompass the entire process of energy transfer from one organism to another. Thus, food chains and trophic levels provide a comprehensive view of how energy moves through an ecosystem.