Hello.
Historians use things such as primary soursces like fossials, Artifacts and documentary evidence. Evidence that a historian uses to study is the written record. Historians use data collected by governments to study what the world was like in regards to numbers and records.
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A Because that is what it is
No, as the current government system has kept everything in order and we have had it for quite a long time, therefore giving us major experience with this form of democracy.