Chen et al (2018) conducted a decomposition experiment on litter collected in Sichuan Province, China. Based off the graphic below what were the ecosystem structure(s) and function(s) considered in their study? Structure: Soil Class, Functions: Nitrogen Fixation + Photosynthesis Structure: Forest Type, Functions; Soil respiration + Decomposition Structure: Vegetation Type, Functions: Decomposition, Carbon Cycling None of the options provided.