4. What is an ecosystem?
a. Living and non-living elements of the environment that interact with one another
b. The living organisms in a habitat
C. The non-living parts of the environment
d. Living and non-living elements that do not interact in the environment
5. What do we call it when the elements of an ecosystem exist in stability?
a. An unbalanced ecosystem
b. A balanced ecosystem
C. A human disturbance
d. A natural disturbance​