The main cause is poverty and lack of education. They're very poor, so they can't afford school. If the children do go to school, they drop out very young to work and help earn money for the family. That's not the kind of cycle people can break out of easily.
Add to that the civil war from 1960 to 1996 where the military persecuted the native people, killing up to 200,000, and they've had a pretty rough time of it.
Humanists believe that people are free to think for themselves.
The correct answer to this open question is the following.
Although there are no options attached, we can say the following.
The most valid counter-argument to the description of the Mongols by the Russian duke was that the Mongols were interested only in plunder and treasure but not in controlling the Russian territory.
As we know by reading this part of history, the Mongols were terrible warriors that showed no mercy. They were fierce fighters that indeed were interested in destroying and plunder. And more than conquering and establish a form of government to rule a territory, by the way, they attacked and proceeded, it seemed that they were more interested in becoming wealthy.