For maximum benefits of a therapeutic back rub, the long, upward strokes should be repeated

I’m going to guess these are the choices: a) recreational skiing developed in the mid-19th century b) it was originally invented as a way of getting from place to place in snowy regions c) downhill skiing is currently the only common form of the sport d) it mostly evolved from snowshoeing- if that’s the cases then the answer would be c) downhill skiing is currently the only common form of the sport

Your answer is b. centers of disease control and prevention. the description is in the name of the agency. : )