That would be 4 Japan, where they dropped the two nuclear bombs in Nagasaki and Hiroshima
Civilizations connected through trade first via trading tools with other nearby communities then it evolved into trading more goods such as foods crops and weapons. Then with boats this allowed technology and customs to travel for example Egyptian sculptures influencing Greek art work and the silk road. This helped humanity since a example of isolation was japan until the Miji Restoration. Humanity needs trade in order to communicate and get things they cannot make in their region of the world.
Answer:
nopeeeeeeeeeeeeeeeeeeeeeeeeeeee
Island hopping was good because they could take the key islands without wasting troops on islands that werent useful to the us