Which best describes abstinence? It is only moderately successful at preventing STIs. It is the only method that is 100% successful at preventing STIs. It is almost as successful as vaccines at preventing STIs. It is the least successful way to prevent STIs.

[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.

Frankie is having difficulty developing a friendship with histeammate curtis. whenever frankie invites curtis to hangout with him at the park, curtis always says that he's busy.what is most likely preventing a healthy relationship fromforming? a)the boys are not being generous with their time andeffort.b)the boys are not communicating.c)both boys are too busy.d)the boys are on different teams.

When a person on a skateboard decides to perform a short, hard ollie, that would be considered muscular endurance. true false