Do the dates on this map suggest an invasion of people or a migration of people

Which best explains parallel forces?

1. what was the purpose of the communist international organization?

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