What was a key reason for the island hopping campaign that defined most of the war in the Pacific ?

After the attacks of september 11, 2001, the united states demanded that

Select 3 oral histories from the section entitled, "oral histories of long walk events", and explain how you would feel if this experience happened to you.

Which 19th century technological advancement would best allow farmers along the mississippi river in iowa to quickly transport their crops to buyers in louisiana?