Organisms that feed upon other living organisms as a source of energy and nutrients are called as _____________. Environmental Science May 22, 2020 Aroma Ann0 A. Producers B. Consumers C. Pests D. DecomposersRelated posts:The source of energy in an ecosystem is __________? Organisms which depend on Producers for nutrition are called __________? Organisms having the potential for interbreeding and producing fertile offspring is called __________? The main energy source for the environment is ___________?