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. New communities, known as suburbs, began to be built just beyond the city. Commuters, those who lived in the suburbs and traveled in and out of the city for work, began to increase in number. Society needs your help!Using your knowledge of this topic, solve the clues to unlock the mystery that holds the key to the ultimate success. Good Luck and stay alert!