Describe the united states’ movement from isolationism to expansion-mindedness in the final decades of the nineteenth century. what ideas and philosophies underpinned this transformation?

America's shift to expansion was a result of several different factors including:

1. Economic interests- At this time, America was mass producing goods more than any other time period in American history to this point. With this in mind, many businesses want to expand their markets.

2. Social Darwinism- This is the idea of the "survival of the fittest." The US felt that our institutions and ideas are superior to those of other countries.

3. Manifest Destiny and Industrialization was the idea that Americans were destined to turned the US to a global expansion.

the fact that could also be added to column b is that during world war ii, specifically between the years 1941 and 1945, japan expanded its territory towards the indonesian territory in what was known later as part of the "pacific war". in that time, japan could conquer the philipines, singapore,   borneo, central java, malang, cebu, sumatra and various other islands of the area, therefore expanding its territory for a brief period of time.

the answer would more than likely a.)falling crop prices  

hope the answer is right and ,either way have a nice day.