How did puerto rico become part of the u. s.?

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

Plz the 10 places that charles darwin stopped at to report his findings, and include dates?

What are three supporting points as to why opium was wrong in the chinese trade? why should it have stopped? (opium wars)