Answer:
It was Kansas. Underlying it all was his desire to build a transcontinental railroad to go through Chicago. The Kansas-Nebraska Act allowed each territory to decide the issue of slavery on the basis of popular sovereignty.
Explanation:
Some reasons were that Native Hawaiians were against U.S. annexation, and the controversy of how US marines used force against the Queen Liliuokalani of Hawaii (held her at gunpoint) and also the fact that President Grover Cleveland himself was against annexation.
European nations had new sources of raw materials and other resources.
D the arrival of Allied transport and glider planes