Explain state building in russia after the fall of the mongols

Russia gained its independence from the Mongol Tatars during the reign of Ivan III the Great ending 200 years of Mongol rule. Ivan III  expanded his domain either by conquest, purchases of surrounding sovereign territories or by leveraging on his diplomatic talent in seeking allegiance from weaker rulers

just finished this it is b. centrifugal force

c)an idealized view of nature. hope this