As the native americans were worked to death and died of diseases, what group of people were brought in to replace them as laborers

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.

Which government entity is given the task of initiating articles of impeachment against the president when the need arises

What did hiram rhodes revels argue for in the senate