Final answer:
The Chinese dynasty that temporarily united the northern and southern parts of China after the Tang Dynasty is the Sui Dynasty.
Step-by-step explanation:
The Chinese dynasty that was founded after the Tang Dynasty and temporarily united the northern and southern parts of China is the Sui Dynasty. The Sui dynasty was established by Emperor Wen in 581 and lasted until 618, when it was replaced by the Tang Dynasty.
One of the main achievements of the Sui Dynasty was the reunification of China after a period of division. The Sui Dynasty implemented various strategies to unite the empire, such as marrying into southern aristocratic families and encouraging northern aristocrats to adopt Chinese-language surnames and marry across regional and linguistic lines.