They have continued to improve and are still used today.
I believe the answer is slavery
The Union blockade of the Southern ports was part of General Scott's Anaconda Plan.
The Anaconda plan involved choking off the Southern supply of goods via a port blockage in tandem with the Union Army coming up, around, and down the Mississippi River and working through the south systemically.
<em>European Americans were still hateful toward Japanese citizens when they returned home from internment camps because;</em>
A. They were still fearful and racist
The murder mass amounts of people by using the way of genocide