Which model of urbanization did edward ullman develop

Harris and Ullman’s Multiple-Nuclei Model

Explanation: Harris and Ullman’s Multiple-Nuclei Model is used to understand and  explain the internal structures of cities and urban areas. It was developed in the year of 1945 and its goal was to move away from the concentric zones and demonstrate complexity found in large urban areas.

first, the romans stayed isolated because they had to defend their own territories from neighboring cities that were harassing them, like the etruscans. second, once the romans managed to defeat their neighbors, and started to expand their territory, they started to build roads and bridges. finally, now that the romans have covered their territory with roads functioning as highways, they could mobilize their legions faster to assemble larger military units in a specific place.

the answer is a wheel