Aré e-cigarettes safe to use? why or why not?

[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.

One hospital ceo insists on including performance data in the hospital’s annual report. “we do very well on most measures, except for one or two, but we put those in anyway,” she says. “we want to hold ourselves accountable.” does this practice demonstrate effective or ineffective leadership?

Adog begins walking at a speed of 6 kilometers per hour. after 1 hour, the dog is walking at a speed of 4 kilometers per hour. which is this an example of? a. positive acceleration b. negative acceleration c. speed