An ecosystem includes all of the living and nonliving factors in a given area. that is, it includes all of the organisms (e. g., plants, animals) that live in an area and the environmental factors (e. g., water, soil, climate) that affect the organisms. what is one criteria that must be met in order for an ecosystem to be stable? a. the amount of available resources in the ecosystem must change at a predictable rate. b. the population size of every organism living in the ecosystem must increase over time. c. there must be less energy flowing into the ecosystem than flows out of the ecosystem. d. the different species of organisms within the ecosystem cannot interact with one another.