Which best describes the result of the mongol invasions of Korea between 1231-1273

Koreans defended their kingdom from the Mongol invasion.

Explanation:

During 1231, Mongol king Ogedei Khan ordered an invasion in Korea against Goryeo empire. These invasions were consist of six campaigns throughout the Korean Peninsula, caused the tremendous cost of civilian life. Throughout campaigns, Korea became a tributary ally of the Mongol Empire (Yuan Dynasty) for about 80 years.

Korea became a vassal state of the Mongol Yuan Dynasty for nearly 80 years.