(A) ** Industry and techology
(B) Plantations
(C) The Oregon Trail
(D) Their Canadian allies
EXPLANATIONS BELOW
Concept note-1: -The Railroad Once again, the Union had the advantage. When the war began, there were 22, 000 miles of railroad track in the North and just 9, 000 in the South, and the North had almost all of the nation’s track and locomotive factories.
Concept note-2: -Technological advancements have been a key factor in war for as long as humans have been fighting each other. The most obvious example of this is the atomic bomb and the nuclear weapons that so called super-power countries have which is claimed to act as a deterrent to war.