Final answer:
A historic activity center built over an older city or town is known as a superimposed city.
Step-by-step explanation:
A historic activity center built over an older city or town is known as a superimposed city. A superimposed city refers to a city that has developed over time with layers of different civilizations and structures built atop one another. The use of a superimposed city involves studying these layers to understand the historical, cultural, and architectural evolution of the urban landscape, providing valuable insights into the city's rich history and the civilizations that contributed to its development.
This term is used to describe cities that have been built on top of pre-existing settlements or cities. Examples of superimposed cities include Uruk in Mesopotamia, Abydos in Egypt, Harappa in the Indus Valley, and Anyang in China.