How was the demand for labor on the "slave frontier" met?

The correct answer is:

Slaves were sold in the South by owners in the border states.

The slave frontier´s expansion led to an increase in the slave trade. This western boundary passed through the middle of Georgia in 1790, and by 1830 it was stretching through Louisiana. By 1860 it was able to extend to Texas. This development in territory raised the number of slave states and the acquisition of land also presented an opportunity for planting crops that needed laborers.

answer: wait what

explanation:

the correct answer is a) egypt and china.

egypt and china are two of the world’s oldest civilizations known by man. both ancient empires have left a great historic and cultural legacy to the world through archeology. both civilzations developed complex social relations, had deep religious beliefs, had dominion of agriculture and left writing records to understand their customs and culture.

among the requirements to consider a civilization, we find urbanization, writing records, a place of residence, agriculture methods, technological specialization, means of transportation, currency, population density, social stratification, and political integration.