During the 1850s to 1950s, the primary focus of the public health effort in the united states was to

Control infectious diseases because in the early 1900s in the United States, many major health threats were infectious diseases associated with poor hygiene and poor sanitation (e.g., typhoid), diseases associated with poor nutrition (e.g., pellagra and goiter), poor maternal and infant health, and diseases or injuries associated with unsafe workplaces or hazardous occupations.

I'm not 100 percent sure i say 7 is your answers