The answer is c. reverse its polarity.
I would say that the Rocky Mts were the youngest of all these mountain ranges as they were created between 80-55 million years ago during the Laramide Orogeny and also they are generally much taller than the other mountain ranges mentioned here which is a characteristic of young mountain ranges and their features are sharper as they haven't been eroded the way most of these others have so have been subject to erosion for less time than the others.
Channel Tunnel, CN Tower, Empire State Building, Golden Gate Bridge, Itaipu Dam, North Sea Protection Works (Netherlands), Panama Canal. Hope this helps!
Silk is not a major Export of Southern Africa This time
This time, the major export of Southern Africa came from Agricultural and Mining Sector, such as : Vanilla, Coffee , Tobacco, Gold, Platinum, Diamond, and Silver
The level below which the ground is saturated with water.
