Think of it as a giant chain. You have the President at the top, then followed by the vice president, and so on to the bottom of the chain. if the first link of the chain is broken, then you replace it with the chain link below it. So, the Vice president would replace the President, the Speaker of the House of Representatives would replace the Vice President, and so on.
Ater the Roman empire collapsed in the west in 476 AD, the bzyantine empire lasted another millennium before being conquered by the ottoman turks
Columbus's arrival in the America's affected the Native Americans in a very negative manner, bringing war and disease. It affected the Africans because it resulted in slavery in U.S, and it affected the Europeans by giving them new land to settle on.
