Key Concept 7.1: Growth expanded opportunity, while economic instability led to new efforts to reform U.S. society and its economic system.

Key Concept 7.2: Innovations in communications and technology contributed to the growth of mass culture, while significant changes occurred in internal and international migration patterns.

Key Concept 7.3: Participation in a series of global conflicts propelled the United States into a position of international power while renewing domestic debates over the nation's proper role in the world.