<span>Yuan Dynasty after Kublai Khan's death-began to fade, families argued over who would rule & Chinese rebels overthrew the Mongols</span>
Because door of world is open for all..
and so U.S entered WW1
1. deficit incurred due to the expenses of a political effort: Debt: to owe money
2. following one's principles: conscientious: somebody is conscientious when he/she performs a job well
3. persons appointed to head the executive departments of the United States Government campaign: cabinet members. Cabinet members are top leaders from the executive department in the US.
4. separation from a main group to form a new group as a result of disunity: segregation. Segregation is to separate someone or something apart from others usually based on religion, race or gender.
5. the removal of legal and social barriers which impose separation of groups: integration. Integration is to successfully mix with a different group of people.
Powers not delegated to the U.S by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people.
So basically, they are reserved to the states and left up to them to decide.
