Americas and Oceania were similar in the way that first they both could developed experienced agricultural practices. Second, they could have their own distinct architecture, art and some other cultural characteristics with any influence from the outside. Third, some external groups sustained their nomadic hunter.-gathering lifestyle. And finally, both of them faced dangers of overpopulation and exposed of diseases they had never been exposed to. They both were different just because they developed large sophisticated societies in isolation merely.
Answer: The last one because it's an opinion not a fact
They reduce the time (by making it faster) and reduce the cost of trading (by making it efficient).
