To get a more accurate idea of our performance, it is best to compare ourselves to people who
A. are better at something than we are
B. come from a different background than ours
C. have a background that is similar to ours
D. are worse at something than we are
Please answer

Name three methods a person can take to protect their skin from the sun. site 1

Describe some of the common health conditions associated with air pollution.

[120 total points] (public health) in one of the largest human experiments ever conducted, in 1954 a randomized controlled trial was run to see whether a vaccine developed by a doctor named jonas salk was effective in preventing paralytic polio. a total of 401,974 children (ages 6–9), chosen to be representative of those who might be susceptible to the disease, were randomized to two groups: 200,745 children (the control group c) were injected with a harmless saline solution (a placebo) and the other 201,229 children (the treatment group t) were injected with salk’s vaccine. what was the point of giving saline solution to the children who didn’t get the vaccine? explain briefly.