Answer:
To quickly determine the difference between a want and need, think of a need being something required for survival. Needs are water for drinking, food to eat, clothing to keep you warm, and shelter to live in. ... On the other hand, a want is everything else. Wants are there to make life a little more enjoyable.
It was the Cotton gin it made things easier and faster.
Leapfrogging or also known as island hopping where the military traveled to another island
In the United States, Congress is not allowed to "favor the trade of one state over another state," since the purpose of the federal government is to address the needs of all states on an equal basis.
