Considering that slavery originated sometime in the 1620s in North America, and that it lasted until 1865, the correct answer to how much it lasted should be around 245 years.
<span>John D. Rockefeller did everything by his own. Vertical integrations means that he employed his own workers, then he constructed barrels to store oil and rent wagons and horses to transport that barrels. So it's called vertical integration. </span>
D Hope that help With your question
