Answer:
The answer is:
It was "invaded," or "reoccupied" by China in 1950.
Explanation:
In 1950, the People´s Liberation Army entered Tibet and established Chinese control again. Since then, it is considered a province of the People´s Republic of China. Tibet enjoys a rich and old culture that is clearly different from Han culture. It was a territorial gain of the Qing dynasty, the last dynasty, it isn´t an ancient Chinese territory.
The answer to this question is 4. Industrialization caused urbanization and a population boom.
