The mongols
a. captured constantinople.
b. stopped the spread of the plague to the west, but allowed it to decimate china.
c. were immune from the yersinia pestis.
d. stopped the spread of the plague to china, but allowed it to decimate the west.
e. facilitated the spread of the plague with the creation of its silk road empire.

e. Facilitated the spread of the plague with the creation of its Silk Road empire.

Explanation:

The Mongols made it easier for the propagation of the Black Death from Central Asia to the west and east thanks to the creation of the Silk Road. The disease reached Europe for the first time during 1347 in the Crimea, precisely the city of Caffa. After sorrounding the city for a long time, the Mongol army catapulted their infected dead bodies towards the city in order to infect its people. This eventually led to a wider spreading of the plague, since Genoese traders escaped by ship to Silicy and Southern Europe.

the answer is b: the religion they practice.

here's why:

there were many different native american tribes and those with similar characteristics formed a main tribe or nation. each had its own language, religion and customs.