1. What is an ecosystem? A. a process in which plants take carbon dioxide from the atmosphere and hydrogen
from water, and release oxygen into the atmosphere
B. a group of living organisms interacting with one another as well as with nonliving
things
C. a predator that lies at the top of the food chain and may feed on plants, primary
consumers, or secondary consumers
D. an organism that attaches itself to dead tertiary consumers and breaks down the
matter of their bodies