Match the following descriptions with the appropriate factor that influences extinction. 1: Dissemination of harmful substances into the environment, such as the pesticide DDT. 2: Non-destructive disturbance of an ecosystem, such as visits to caves that disturb bat hibernation. 3: Disturbance of an ecosystem with the creation of disconnected portions of the habitat, such as converting a section of a forest into farmland. 4: Species interactions are changed as a result of the behavior or abundance of a species, such as a trophic cascade.