What impact did railroads have on cities across the united states at the turn of the twentieth century?

Travel from place to place now became easier with the number of tracks that connected the states with each other.  Apart from that, transport of products was now easier resulting in the increase of business all over the country thanks to the railroads.

two jet streams that directly affect the formation of weather in the continental part are a polar jet and a subtropical jet. they are responsible for the transportation of weather systems, which directly affect people. the polar front is the boundary between cold air from the north pole and warmer equatorial air. both the polar jet and the subtropical jet blow from the west to the east, and follow the boundary between cold and warm air.

the strongest jet streams are polar jets, while subtropical jets are somewhat weaker.

the right answer is c. the polar jet stream is generaly stronger than the subtropical jet stream.