Answer: Industrial expansion and population growth radically changed the face of the nation's cities. Noise, traffic jams, slums, air pollution, and sanitation and health problems became commonplace. Mass transit, in the form of trolleys, cable cars, and subways, was built, and skyscrapers began to dominate city skylines.
Explanation: Resizing and growth changed the face of the nation's cities. It was very noisy, there was air pollution and health problems became common.
