What did the europeans use coal for?

Ineed because i cannot find the answers anywhere

What was the midwest states often called because they were located in the center of the nation

Which of the following studies is linked most directly to the establishment of the national research act in 1974 and ultimately to the belmont report and federal regulations for human subject protection? a. the public health service tuskegee study of untreated syphilis in the negro male.b. stanford prison experiment (zimbardo).c. tearoom trade study (humphreys).d. the harvard t3 study.