The sun provides light to plants and algae, which make up the first trophic level of an ecosystem called the producers. the autotrophs are what heterotrophs consume, particularly herbivores, which make up the second trophic level. now these herbivores are also consumed by other heterotrophs, those who are in the third trophic level.
A. Primary consumers
B. Secondary consumers
C. Tertiary consumers
D. Decomposers