A protective tariff is taxing a foreign good to protect it from foreign theft. Tariff means tax, and protection means what it sounds like, so all together it means a protective tax
Even though slavery was abolished, that did not mean the white people would stop treating the black people with a lack of respect. Thus lead to segregation some years later, and then resulted in the civil right movement.
The ideas of the Enlightenment helped lead to the American Revolution and American independence because they formed the philosophical basis for America’s claim that it should have more autonomy.
The likely effect of such trail lines that were left by pioneers migrating to the west were that people who moved there afterrwards were able to derive information regarding where it was relatively safe and where territory has been charted and mapped before. This enabled a little certainty in areas of great danger.