What kind os source would a historian use to get a firsthand account of a past event

Legacy of the new deal is positive or negative

Who did the first work in creating vaccines

What were copernicus’s ideas about the order of the universe deemed to be dangerous to church thinking? (5 points) a. the church was invested in the idea that the earth was at the center of the universe b. copernicus was developing a new religion that would challenge the church c. the church feared his ideas threatened their control of european universities d. copernicus was a follower of luther and therefore could not be trusted