Earthworms play multiple roles in the ecosystem, both as "consumers" and "creators". It feeds on soil substances through activities such as feeding, digestion, excretion (earthworm dung), secretion (mucus) and burrowing. Contributions to circulation and energy transfer can have an important impact on multiple processes that determine soil fertility. It is known as the "Ecosystem Engineer" and is also considered the "first worker" on earth. Everything it does in the soil The activities are all "transformation" of the soil environment, and its life activities are essential in the small cycle of soil material biology. The most likely next paragraph of this text is:. ['Ecosystem cyclic processes.', 'Factors affecting soil fertility.', 'Soil modification by earthworms.', 'Living habits of earthworms.']