a. The logistic equation reflects the effect of density-dependent factors, which can ultimately stabilize populations around the carrying capacity. b. Density-independent factors have an increasingly greater effect as a population’s density increases. c. High densities in a population may cause physiological changes that inhibit reproduction. d. Because of the overlapping nature of population-regulating factors, it is often difficult to precisely determine their cause-and-effect relationships. e. The occurrence of population cycles in some populations may be the result of crowding or lag times in the response to density-dependent factors.