urbanization-
when the population grows and increases the amount of people in a given area.
The correct answer is - urbanization.
The process of urbanization is the one associated with the growth and development of the cities. This process takes place when there's a growing population in a city, both caused by fertility rates and migration towards it, so the local authorities are making the peripheries of the cities and surrounding villages modernized and start to put institutions in them, as well as the necessary modern infrastructure.