Answer:
A reference point is a place or object used for comparison to determine if something is in motion. An object is in motion if it changes position relative to a reference point. Objects that are fixed relative to Earth – such as a building, a tree, or a sign - make good reference points.
Explanation:
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3. all the living things in the forest ecosystem.
When the upper water layers warm in the summer months, they become separated from deep water by a transition zone known as a thermocline. In a thermocline, the temperature decreases rapidly with small increases in depth. This phenomenon linking temperature change with depth is called temperature stratification.