the border between the United States and Canada lies at the latitude of 49 degrees the blank is located at 0 degrees latitude and passes through the nation of the blank is located at 0 degrees longitude and passes through the ​

Which of these would be most useful in studying the effect of germs exchanged between the new and old worlds? a. a graph showing the number of europeans between 1492 and 1600. b. a graph showing the number of native americans between 1492 and 1600. c. a primary source description of the symptoms of an unknown disease affecting native americans in 1492. o d. a primary source description of the symptoms of an unknown disease affecting europeans in 1492.