When polynesia was settled, became a key to survival because each island had different resources.

If they couldn't have produced all the necessities locally (since they didn't have the resources) they would have to get it from somewhere else - by trade (trade is the correct answer). So they needed to organize a trade system with the other islands to exchange the goods that were needed.

Ongoing civil wars western roman empire finally collapsed476 c.e. romulus, the last of theroman  emperors in  the west, was overthrown by the germanic leader odoacer, who became the first barbarian to rule in rome. the order that the  roman empire  had brought towestern  europe for 1000 years was no more.