Final answer:
Due to problems with water drainage, people often settled on the plains which were part of the city's environment. The terms that complete the list are Hills, Valleys, Mountains, Deserts, Plateaus, Islands, and Plains.
Step-by-step explanation:
Because of the problems that were caused by uncontrolled water drainage, most people lived on the plains that comprised the city. They were named: Hills, Valleys, Mountains, Deserts, Plateaus, Islands, and Plains. The early urban centers in Mesopotamia, particularly in the southern region of Sumer, arose due to the necessity of managing the natural resource of water.
Irrigation systems were essential for controlling the unpredictable Tigris and Euphrates rivers, which were prone to periodic flooding. This led to the establishment of leadership, governance, and eventually the creation of cities. Similar issues of water management and settlement patterns were observed in the Indus Valley, where a highly complex society developed comprehensive urban planning and water resource systems.
In contrast, the inhabitants of the Great Plains in America led a nomadic lifestyle, relying on hunting and the environment, while tribes in the Plateau region lived in stable communities near rivers and streams with abundant natural resources.