Final answer:
The Grand Canal was built by the Chinese to enable trade and transportation between the Yellow River and the Yangtze River, crucial for distributing grain from south to north and bolstering the economy.
Step-by-step explanation:
The Chinese built the Grand Canal to allow trade between the Yellow River and the Yangtze River. This waterway, with portions dating back to the 5th century BCE, was majorly extended and connected during the Sui dynasty, forming a continuous 1,100-mile route from Hangzhou to Beijing. Not only did it play a crucial role in moving southern-produced grain to the north, but it also facilitated the movement of troops and integrated the northern and southern regions of the empire.
The main canal was more than 130 feet wide and included an imperial road alongside it for easier communication and transportation. It also featured relay stations for efficiency in trade and travel. Over time, it became a critical artery for rice transport from the Yangtze valley, as well as for other goods, fostering a booming era of trade and economic development throughout China.