Here were the choices on that question:
a. poverty
b. lack of adequate rivers
c. mountains
<span>d. richness
The answer is D. richness. Based on A Companion to World History, the African Sahel can be a corridor of communication between Nile and Niger valleys but did not materialize. The reason was the richness of Sahel that it that it can provide for itself even without trade.
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Convection currents occur in the MANTLE. The mantle is the second layer of the earth after the crust. The mantle is approximately 2900 km thick. Convection currents are triggered or fueled by the heat from the Earth's core.
The part of the mantle closest to the core gets heated. It then becomes less dense than the layers above so it rises. When this rising plume interacts with the crust it cools and becomes more dense than the layers below and so it sinks and this circular motion continues to form convection currents.
A. Spin because in a twirling motion tend to become a spinning type of motion. I think
Answer:
A. Global Positioning System (GPS)
Explanation:
The Global Positioning System (GPS) is the most accurate way to find your exact location, virtually anywhere on the planet, thanks for a large network of satellites orbiting the planet and providing location information. That system is also complemented by the cellular towers if you're using a cell phone.
Aerial photography is great, but it will not tell you where you are.
Remote sensing is to gather information from a distance, not relevant to the question here.
The Geographic Information Systems are information systems to give information about the land matched with precise GPS information, used in mining for example, but it's not able to tell you where you are, it's to tell where a gold deposit is however.