How does periodization us to study history

Which source would best a historian understand the effect of the great chicago fire on families? a. a biography of a chicago family displaced by the fire b. a letter from a grandmother in new york to her family in chicago c. a newspaper editorial about families who were displaced d. an oral history dictated by an adolescent who fled the fire

Which of these events was a severe setback for the u.s. war effort in the pacific?

What is the meaning of the phrase “bear ’t”? what word is left out between the words but and few?