Final answer:
Indus Valley cities are documented to have traded with Mesopotamia, with archaeological evidence of trade items and references to the Indus Valley in Mesopotamian records. While trade with other regions is less definitively documented, the civilization had advanced urban planning and trade networks.
Step-by-step explanation:
The Indus Valley cities are known to have traded with cities as far away as Mesopotamia, and there is evidence suggesting connections with other regions as well. However, when it comes to definitive historical evidence, the most well-documented external trade relations were between the Indus Valley and Mesopotamia. Archaeological discoveries have unearthed references to the Indus Valley in cuneiform tablets from Mesopotamia, revealing that precious stones like lapis lazuli and carnelian, and marine shells were important trade items. Additionally, Mesopotamian merchants traveled across the Indian Ocean and the Iranian plateau to conduct their business.
Even though the actual extent of the Indus Valley Civilization's influence remains uncertain due to a lack of written records, it is clear that it was an advanced and well-organized society. Cities such as Harappa and Mohenjo-Daro exhibit meticulous urban planning, with sophisticated water management systems and industrial areas, which indicates a high level of technological and social organization. Within their economies, this civilization had thriving craftsmen and merchants, suggesting that trade and commerce were significant aspects of their culture.
Given this context, the answer to the student's question is that Indus Valley cities traded with cities as far away as Mesopotamia, and from available evidence, a definitive trading relationship with Egypt, China, Persia, or Greece is not as well established.