A cause was that Texas declared its independence from Mexico. It changed the U.S. by the U.S. gaining California, New Mexico, Utah, Arizona, Colorado and parts of Wyoming.
The problem centered around factories that used a new based technoloy.
Andrew carniege installed a lot of new inventions in order to increase the efficiency of his production. This ended up making a lot of skilled workers to lose their jobs/position in the industry and replaced with low skilled worker to operate the machinary.
It would be B because it explains it better
Answer: 13. New York
14 after the city of Le Havre in France.
15.Musician teacher humanitarian
16. Alexander Hamilton
17. 15,439 square miles
18. twenty-four hours a day, six days a week