They are based on layers of rock the correspond to certain time periods, so my guess would be D.
Answer:
Explanation:
Distance and direction of an object's change in position from a starting point. Displacement. 3. Jermaine runs exactly 2 laps around a 400 meter track. What is the displacement? 0 ... David walks 3 km north, and then turns east and walks 4 km. ... A person walks 50 meters directly north, stops, and then travels 32 meters
A its Stratosphere, Sorry I didn't see your answer, its bilogy I think not physics.. :)
