Which source would best a historian understand how the great chicago fire affected families?

The best source to understand how the Great Chicago Fire affected families would to simply ask those affected by it.

Public documents from the time, such as those that can be found in the Chicago Public Library.

Explanation:

Since the Great Chicago Fire took place in October 1871, the most reliable source to understand how the tragic event affected families would be an official document that keeps track of the statistics regarding the incident (such as how many people were killed by the fire and other consequences).

Taking this into account, a reliable source of information could be the Chicago Public Library, founded after the fire took place. There, written documents and reports should shed some light on the issue.

Furthermore, to get an idea of how the fire affected lives, real photographs, works of artists and newspaper articles from the time could also count as reliable sources.

the british won and the germans couldn't invade great brit

b) the confederacy had to pay all union war expenses.