D. To isolate people who were believed to be threats.
America used these camps after the bombings of Pearl Harbor. They believed that Japanese were a threat to the country, so they has them put in internment camps.
The United States made use of internment camps for fear the involvement of immigrants to their home countries - mainly Japan, who had just attacked Pearl Harbor.
</span>d. to isolate people believed to be threats<span>
The Industrial Revolution led Europeans to have better military weapons and this allowed small European armies to defeat larger African and Asian forcer when invading territory. This made possible the colonization of the African continent.