What events and forces prompted the expansion of american slavery between 1790-1820? how would you describe the slave trade?

The expansion of American slavery was impelled due to agricultural development. The amount of land is so vast that cultivation needs hundreds of workers to sustain the tobacco and cotton crops. With this, property owners uses slave, mostly from Africa to sustain the growing business. Moreover, slave trade was largely distributed throughout North and South America. The prices of slaves varied over time due to factors that includes supply and changes in the prices of commodities, especially cotton. Keeping slaves are profitable specifically the adult female where they can work in the field, at the same time they were able to have children that eventually became slave when they grew up. Thus, their value are much higher than men.