Answer:
Primary source
In the study of history as an academic discipline, a primary source is an artifact, document, diary, manuscript, autobiography, recording, or any other source of information that was created at the time under study. It serves as an original source of information about the topic.
Civil War killed off slavery and declined the southern economy it also acted as a catalyst to make America into a complex industrial society of capital, technology, national organizations, and large corporations.
League of Nations.
It fell apart because it failed to stop WWII (partially because the US didn't join it), and after WWII, the United Nations was created.
