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The "driest" area of Midwest region would most likely:
![Great \\ Plains](https://tex.z-dn.net/?f=Great%20%5C%5C%20Plains%20)
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In areas where cool dry air masses frequently collide with hot humid air masses
The answer to the question above is Bowen's reaction series. In geology, the reaction is work of a petrologist by the name of Norman L. Bowen. He explained why some minerals are found together and some others are not associated with one another.
Answer:
River A is the Congo River. River B is the Zambezi River.