What changes were brought about due to the expansion of the railroads?

In the 19th century (before as well as after the Civil War),  railroads brought many changes to the United States of America. For  one thing, trade and commerce increased, with a complementary expansion of industry, especially in the North. For another,  settlement of the 'wild West' was made easier, as was increased  growth of areas already settled. For yet another, military operations became more sophisticated and generally more  power-packed: during the Civil War, Union and Confederate forces  could be quickly reinforced or moved to areas of special need due to the rapid transportation provided by railroads.

increases in demand are shown by a shift to the right in the demand curve. this could be caused by a number of factors, including a rise in income, a rise in the price of a substitute or a fall in the price of a complement.

which the answer is:

b

there are more than a million jobs out there

explanation:

they pay you money for doing work