Question: why tibet is part of china?
Answer: The Republic of China (ROC) asserted that "Tibet was placed under the sovereignty of China" when the Qing dynasty (1644–1912) ended the brief Nepalese rule (1788-1792) from parts of Tibet in c. 1793. The Tibetan Government in Exile asserts that Tibet was an independent state until the PRC invaded Tibet in 1949/50.