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.
The answer is "New England"
An open compound is a word where an adjective is added and creates a new noun, so "New" is added to "England" to create a new noun "New England"
another example of an open compound would be "peanut butter"