the salk poliomyelitis vaccine was tested on ~1 million children in 1954. in early 1955 the data came in that the vaccine was efficacious and safe

frederick william of brandenburg-prussia trained his son, frederick, to be a hardy soldier. but frederick disliked rifle shooting and horseback riding. unlike his father, he was interested in french literature. he enjoyed poetry and music and, like some others of the enlightenment, he scoffed at religion. his father thought him soft, frivolous and unmindful of his duties. and when frederick refused to put his signature on a right to succession, for a few moments his father strangled him.

d) iowa i believe is the answer

1775 is your answer hope this