Free Points! :D please dont report

Sam is a four-year-old child. as compared to other boys of his age, his skin looks dull. his hair appears damaged and dry. which nutrient is sam’s body likely lacking? a. proteins b. carbohydrates c. fats d. minerals

[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.

If a person has a bad pain in their back, specifically lower back a bit above the hip, what should they do besides going to the doctor? what remedies could they use?