Explanation:

The term 'ecosystem' was coined by the British botanist Sir Arthur Tansley in 1935. He defined it as the whole system, including not only the organism-complex but also the whole complex of physical factors forming what we call the environment. This concept emphasized the interconnectedness of living organisms and their non-living surroundings. Option B, Eugene Odum, is known as the 'father of modern ecology' and popularized the ecosystem concept, but he did not coin the term. Option C, Eugenius Warming, was a pioneering plant ecologist. Option D, Charles Darwin, is famous for his theory of evolution by natural selection, not for coining 'ecosystem'.