I want to know the answer to the following question:
What facilitated the rise of Sumerian cities?
All the background I'm provided with is that "By the time of the Uruk period (c. 4100–2900 BC calibrated), the volume of trade goods transported along the canals and rivers of southern Mesopotamia facilitated the rise of many large, stratified, temple-centered cities (with populations of over 10,000 people) where centralized administrations employed specialized workers.". Is that enough to answer the question?
Answer: yes