Answer:
Sorry I only know the downfall.
Step-by-step explanation:
What led to the fall of the Mongolian empire, is that they were good fighters, but not so good leaders. Another thing that led to the fall of the Mongolian empire is that the 'leaders' didn't know how to manage such a large empire. The Mongols continued to expand their land even if it was too much for them to handle.
Around 1330, the Black Death disease started spreading which also lead to the downfall. It spread because merchants along the silk road got it from rats that carried deadly plague diseases.
Hope this helps c(o.o(c