Select the TWO answer choices that, according to paragraph 4, are conclusions that can be drawn from the study by Tilman and Downing. To receive credit you must select TWO answer choices. A. A diverse ecosystem will have species that respond differently to a variety of conditions. B. Species within a species-rich ecosystem are more likely to have competitors. C. An ecosystem is more likely to develop diverse and stable species when it is exposed to extreme conditions. D. Species with similar ecological functions will perform the function of a lost species.