When organisms in an ecosystem need the same resources, what occurs?
If an ecosystem is unchanging, it is _______________.
What is it called when something moves through a series of steps that repeat?

What is the order of the food chain? List in order of bottom of the chain to the top of the chain.

Which statement best explains what happens to the ray population when the shark numbers fall?
Which animal pair includes two competitors?
Which of these is NOT a characteristic of a healthy ecosystem?
Organisms store very little energy from the food they eat.
Organisms can carry on life processes without every recharging their energy.
The first step in the cycle of matter happens when ________________ take in matter from the air, soil, and water.