Final answer:
Sumer is classified as a civilization because it met the criteria of a civilization, including urbanization, agriculture, a writing system, a centralized government, social stratification, and technological advancements.
Step-by-step explanation:
Historians classify ancient Sumer as a civilization because it met the criteria of a civilization. A civilization is a complex society characterized by urbanization, the development of agriculture, a system of writing, a centralized government, social stratification, and technological advancements. Sumer had all of these characteristics.
For example, Sumerian cities such as Uruk and Ur were densely populated and had advanced infrastructure and architecture, including monumental temples and palaces. The Sumerians developed a sophisticated writing system called cuneiform, which allowed for written records and the communication of ideas. They also had a centralized government ruled by kings and priests, and a social hierarchy where priests, nobles, and commoners had different roles and responsibilities.
Furthermore, Sumerians were skilled farmers who developed irrigation systems to support their agricultural practices. They grew crops such as barley, wheat, and dates, and domesticated animals such as sheep and goats. These agricultural surpluses allowed for the growth of urban centers and trade.