Answer: B. A writing system
Explanation: The Sumerians are the first known world civilization, which emerged on the land of Mesopotamia. In addition to the Sumerians, there were other Mesopotamian civilizations after, but one of the most important inventions or achievements that had an impact on the development of later civilizations was the writing system. It can be said that this invention is of great importance in general. According to some archaeological finds, the oldest Sumerian writing system on clay tablets dates back to the 8,000 years BC. To write on clay tablets, a Sumerian cuneiform was used, originating from pictographs and some other symbols used to display trade goods. The cuneiform was created from the need for trade because it represented a system of writing using wedge-shaped symbols, which were simpler than image symbols.
