The Columbia Exchange was the first major transfer of a plethora of different goods between the New World and the Old World, meaning that it made colonies in the New World more appealing because food and resources were supplied.
The columbian exchange improved the European diet by improving its taste. This was done by increasing Old Worlds' abillity to feed more people. This made the colonies seem more appealing to people.
It proclaimed the freedom of slaves in the ten Confederate states still in rebellion. It also decreed that freed slaves could be enlisted in the Union Army, thereby increasing the Union's available manpower.
Yes, teens think they have to do something in order to be cool and not get bullied. Like drinking, teens being pressured by their friends to drink and if they don't their not cool, is an example.