How did industrialization lead to imperialism?

Which term do historians use to describe the personal preferences that people have that affect their interpretation of events

In italy, the distance between milan in the north and palermo,sicily, in the south is about 550 miles. in the united states, the distance betweenboston, massachusetts, and savannah, georgia, is about 900 miles. do you think the american revolutionaries of 1776 in the 13 colonies faced some of the same challenges as the patriots who struggled for italian unity in the 1860s?  

To what extent do you think the roman republic was democratic?