The people were extremely poor and tired of political and economic occurrences. Nobles were getting richer together with the king while the people were living worse and worse. They were also always forced to go into wars that they didn't want to fight across Europe just so the king could fill up the bank again that he would spend on food and clothes. Everyone was angry and started gathering into clubs, which were something like early types of parties.
The Battle of Verdun is considered to be one of the most brutal events of World War I, the site itself is remembered as the "battlefield with the highest density of dead per square yard."
- The Mongols used qualified people wherever they were needed/Mongols placed Arabs in Russia/Persians in China because they were qualified
- Working bureaucracies were kept in place
- Many local rulers maintained their position as long as they paid tribute/provided troops/pledged loyalty/kept good order
- Chinese bureaucrats still did their jobs as long as they did not cause the Mongols any trouble
- Local Persian rulers stayed in power if they cooperated
These are five examples of answers, hope one can help you!