Hawaii first drew the attention of the United States because it was seen as a refueling station for naval vessels. The correct option among all the options that are given in the question is the fourth option or option "d". I hope that the answer has come to your great help.
A biggie: the transcontinental railroad. Because it would economically improve wherever it was, both the North and the South competed for the railroad to be in their respective territory, evidenced by the Kansas-Nebraska Act and the Gadsen Purchase and induction of California as a free state in 1860.
In addition: people could get land cheap because it was abundant and might leave to start afresh economically.
There's other stuff I can't remember as clearly, but there's a little and I hope it helps :)
89 percent of the ocean would be sea ice
