Who received important ports, cities, and concessions in Southeast Asia in return for not interfering with British shipping?

China

Explanation:

The Chinese are the South East Asian country which received important ports, cities, and concessions in return for not interfering with British shipping.

During the First Opium War the Chinese didn’t interfere with the British importation of weapons and other food materials which were needed for their army which made the British repay the goodwill by setting up several structures for the Chinese people.

the second significant cause of the great migration was the desire of black southerners to escape segregation, known euphemistically as jim crow. rural african american southerners believed that segregation - and racism and prejudice against blacks - was significantly less intense in the north.