Without the mountain lions, increased numbers of deer may reduce the food supply available to other herbivores, such as field mice and crickets. As a result, populations of deer, mice, and crickets might decline, causing a population decrease in species that feed on these organisms as well. This example implies that properly functioning predator/prey relationships do which of the following?
Select all that apply.

A: harm all of the organisms in an ecosystem B: throw an ecosystem out of balance
C: result in food surplus for the entire ecosystem D: maintain balance within an
ecosystem