Which theory emphasizes industrial and demographic changes rather than a single central business district?

The Multiple Nuclei Theory is the correct answer because it recognizes that cities can develop multiple centers of activity, or "nuclei," rather than being structured around a single central business district. This theory was introduced by Chauncey Harris and Edward Ullman in the 1940s as a response to the limitations of earlier urban models such as the Concentric Zone Theory, which posited a more simplified structure where different social groups were organized in concentric circles around the center.

The essence of the Multiple Nuclei Theory lies in its understanding of how urban land use is affected by various factors, such as industrial developments and demographic shifts. These dynamics lead to the formation of several specialized districts that cater to different social and economic functions, such as industrial areas, commercial centers, and residential zones, distributed across the urban landscape.

This model effectively caters to the reality of modern urban form, where factors like transportation trends and population movement create diverse nuclei that respond to various needs and influences. Such complexity in urban structure challenges the notion of a singular point of focus and highlights the multifaceted nature of urban growth and organization.