Final answer:
Many cities formed in southern Mesopotamia by 3000 BCE, in a region known as Sumer. The Sumerians were an advanced civilization with many technological advancements.
Step-by-step explanation:
In southern Mesopotamia, many cities had formed by 3000 BCE. This region was known as Sumer and it was the birthplace of the Sumerian civilization. The Sumerians were an inventive and advanced people, responsible for the development of many technological advancements, including a sophisticated writing system.