PLEASE TAKE A PICTURE OF THIS PICTURE AND FILL IT OUT! I WILL GIVE ADDITIONAL POINTS AFTER, BRAINLIEST, FIVE STARS, AND I WILL HELP YOU WITH ONE OF YOUR QUESTIONS! I WILL ALSO FRIEND REQUEST YOU!!

[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.

When lifting heavy loads off the ground, the majority of the weight should be lifted by which of the following? a. arms b. legs c. back d. stomach

Astairway has 6 steps. is it a handrail required? a. a handrail is required b. a handrail is not required c. double handrails are required d. only nosing is required