PLEASE HELP I WILL GIVE BRAINALIST TO THE FIRST PERSON

Which factor has played the most important role in changing the way history is studied over time?

Erugent which russian tsar defeat napoleon and saw himself as the leader of european monarchs who opposed revolutionary change ivan the terrible ivan the great nicholas 1 alexander 1

Which statement describes an important outcome of the congress of vienna? a. napoleon launched his final european military campaigns. b. european states had their borders clearly defined. c. jewish people were given equal right in germanic states d. the slave trade became increasingly important to european economies.