The chairpersons of the powerful congressional committees are a. chosen in a nationwide election b. elected by the full membership of congress c. appointed based solely on seniority regardless of party affiliation d. members of the majority party who are appointed by the majority party leadership e. evenly divided between majority and minority party members

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.