Final answer:
A megalopolis combines megacities and surrounding areas into a vast urban expanse. Despite the economies of scale offered by cities, diseconomies like traffic and pollution can arise from high density. The challenge lies in managing these effects for sustainable urban growth.
Step-by-step explanation:
A megalopolis merges megacities and nearby populated areas into an even larger mass of people. This phenomenon is indicative of a shift in population dynamics, particularly in the United States where a substantial majority, about 80%, now resides in metropolitan areas, up from 40% in 1900. These urban clusters consume vast amounts of natural resources and shape the U.S. landscape significantly.
While cities provide economic advantages due to economies of scale, they also present challenges when the concentration becomes too dense, leading to diseconomies. Issues such as traffic congestion, pollution, and heightened crime become prevalent. The future of urban development in the U.S. and around the world on balancing these advantages with the negative impacts of high-density living.