Answer:
D
Explanation:
They said shortly after the U.S. military left they fell to North Vietnam
A lack of railroads affected a lot of things. For example like getting supplies or not having job opportunities due to not having a railroad. Also without have a railroad it made traveling harder.
European powers were running out of places to colonize in africa, while trade in East Asia was becoming more and more profitable, but the cost in time and money of traveling all the way around africa and through the india ocean (or the long trek down the silk road) was hampering European profits off of trading. So the Spanish sent Columbus to find a shorter root to Asia. Columbus didn't set out looking for America, it was just a happy accident.
