Improvements in transportation and communication during the fi rst part
of the 19th century aff ected economic relations between regions of the
united states by
(a) making the regions more interdependent
(b) making the regions more self-suffi cient and independent
(c) making industrial regions economically dominant over agricultural
regions
(d) making agricultural regions economically dominant over industrial
regions
(e) furthering individual states’ ability to regulate interstate commerce