The only option that is not generally a reason why historians study societal change would be "<span>d. to estimate how long it would take to build a road system," since this requires a separate type of research. </span>
Hello
The correct answer is Isolationism
Becasue isolationism is where a country does not let anyone in or out of its borders and it does not participate in worldly afairs. It also has isolation in the name and the definition of isolation is the process or fact of isolating or being isolated.
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