Pls help its 6th grade history its easy too

Space is not completely empty. there are small particles in space. what happens when these particles come together?

How did geography influence the development of the byzantine empire?

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