Answer:
The Great Plains undergo changes from one year to another. These changes are determined by the production of floods, the accumulation of sediments or changes made by man (dams, construction of dams, gravel pits).
The Rocky Mountains shrunk annually. External factors (water, air, wind, freeze-thaw process) cause changes in the structure of the rocks and so there are changes in the mountain landscape.
Just look up 2 mega cities (question)
So like New York City location
New York City brief history
New York City population density
Hope this helps.
The Sahel Region is the region that borders between the Sahara Desert to the North and Sudanian Savannah to the South. The countries which are known to traditionally make up the Sahel region are the Gambia, Senegal, Mauritania, Mali, Burkina Faso, Algeria, Niger, Nigeria, Cameroon, Chad, Sudan, South Sudan and Eritrea. Although the entirety of these countries are not considered all to fall within the Sahel Region.
Answer: Principle of Superposition
Explanation: In an otherwise undisturbed sequence of sedimentary strata, or rock layers, the layers on the bottom are the oldest and layers above them are younger. Principle of Original Horizontality: Layers of rocks deposited from above, such as sediments and lava flows, are originally laid down horizontally. Hope this helps!