Answer:
Some of the significant contributions of Genghis Khan were:
He unified the Mongolian steppe.
He challenged the Chinese Jin dynasty.
He created a large territory as Mongol territory stretched up to the Caspian Sea.
Who is Genghis Khan?
He was the Mongol warrior-leader who was one of the most successful military commanders and warriors that helped to unite the Mongolian steppe.
Hence, Kublai Khan was the fourth son of Tolui and also one of the rulers of Mongols, and was also the grandson and greatest successor of Genghis Khan.
the Mongol Empire collapse for a number of reasons. the Mongols were Nomads whose Customs were suited to conquering but not ruling a large empire. the Mongols in distant Khanates were minorities, and many Mongol rulers in these places adopted local customs. Some places such as Russia cooperated with their Mongol rulers but others rebelled and the Empire eventually fell apart.