Is it true that slavery only affected africans

How and why did the 27th amendment modify the authority of congress to set its own pay

Why was frederick douglass encouraged by the dred scott decision?

How does specialization enable countries to trade with one another? a country can make and sell goods affordably and buy goods that it is inefficient at making. a country can make what it chooses and sell its goods to other countries. a country can decide to buy everything it needs from other countries. a country can efficiently make goods that were once difficult to make.