Answer:
The mechanical reaper
Explanation:
He invented the mechanical reaper to do the harvest in fields.
His invention seems rudimentary today compared to the huge machines currently own by large farming companies, but that started it call and allowed to ease the burden of the harvest.
It also provided an alternative to slaves harvesting the fields in many situations.
Answer:
white southerners must promise not to practice slavery anymore
Explanation:
Let us choose Extra study. Knowing that opportunity cost is related to the opportunities lost by choosing one specific course of events than others. By choosing an extra study and spend hours studying something, my opportunity cost will be the school sports practice hours that could be spent in this time. Another opportunity cost would be the social interaction, in a club, for example, lost because of the extra study decision.