GRE Reading Comprehension: ETS-GRE阅读ETS - 1Q56WXM47I64FC537

Which of the following statements can be inferred from the last paragraph? A. For irregularly fluctuating populations, doubling the number of observations made will probably result in the isolation of density-dependent effects. B. Density-dependent effects on population dynamics do not occur as frequently as do density-independent effects. C. At present, ecologists do not understand any of the underlying causes of the density-dependent effects they observe in population dynamics. D. Density-dependent effects on growth parameters are thought to be caused by some sort of biochemical "signaling" that ecologists hope eventually to understand. E. It is sometimes possible to infer the existence of a density-dependent factor controlling population growth without understanding its causative mechanism.