Which factors caused crops to stop growing in sumer?
choose all answers that are correct.
a. poor drainage
b. salty soil
c. extended droughts
d. pest infestations

Soon-yi's house has a hexagonal window made up of six identical equilateral triangles as pictured below.

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

Who did the first work in creating vaccines