What was the main idea of the monroe doctrine?

it was a proclamation of war between the u. s. and mexico.
it was a warning for european countries to stop colonization in the western hemisphere.
it was an agreement to give territories to the native americans.
it was a list of complaints from the u. s. to european countries.

the mongolian invasion of china and central asia resulted in a disruption of the silk road as the chinese garrisons lost support from the chinese kingdoms which fell under the mongols. however, as the mongols established a formal dynasty in china, the successors of genghis khan restored the garrisons along the silk road allowing the safe travel caravans again.