What are two areas of the american colonial economy that african slaves directly contributed to?

Using the pictures and text for reference describe what had to be done to create the central park today

In ohio in 1872, the cleveland massacre was a violent labor dispute at standard oil refineries in cleveland. a takeover by standard oil of the refineries in cleveland. an attempt to stop standard oil from becoming a monopoly. a failed attempt by standard oil to take over other refineries.

How did the united states ironically create a slaverybased market economy and democratic political system?