Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information. A. Unlike the terms "climax", "biome," and "superorganism," which refer to the particular association of plants and animals at a given location, the term "ecosystem" refers specifically to the physical factors within an environment. B. The terms "climax," "biome," "superorganism," and "ecosystem" all refer to the system of plants and animals in an associated environment, but some are more controversial than others. C. When the older terms of ecology became too technical, they were replaced by the more popular and more widely used term "ecosystem." D. The term "ecosystem" gradually replaced discredited terms for the combination of a physical environment and the plants and animals living together in it.