Answer:
British colonies and us U.S. citezens
I'm not sure but I think it's coal mining
https://www.quora.com/What-gifted-musician-was-heavily-involved-in-the-1960s-Civil-Rights-Movement-with-Martin-Luther-King-and-Caeser-Chavez try this link, someone asked the question here
<span>During that time, about 1.5 million Cambodians out of a total population of 7 to 8 million died of starvation, execution, disease or overwork. I wasn't sure on this one sorry</span>