Non-renewable resources are resources for which there is a limited supply. The supply comes from the Earth itself and, as it typically takes millions of years to develop, is finite. Non-renewable resources can generally be separated into two main categories; fossil fuels and nuclear fuels.
But there were pockets of the North on the eve of the Revolution where slaves played key roles in the economic and social order: New York City and northern New Jersey, rural Pennsylvania, and the shipping towns of Connecticut and Rhode Island.
Nearly a quarter of the Africans brought to North America came from Angola, while an equal percentage, arriving later, originated in Senegambia. Over 40 percent of Africans entered the U.S. through the port city of Charleston, South Carolina, the center of the U.S. slave trade.