The correct option is C Forests
Forests provide excellent introduction to the foundational concepts of ecology, since they are among the most structurally and biologically diverse of the planets ecosystems. Forests are built upon highly complex relationships between living and non-living components. In a forest, abiotic factors include fundamentals such as sunlight, moisture, nutrients, bedrock and topography. Biotic components are the living members of the system. A defining trait of an ecosystem is the cycling of nutrients and energy between organisms and their environment, and it is these abiotic components that provide the foundation for interaction between members of ecological communities.