What are the five food groups recommended by the usda’s my-plate food guidance system?

a. fruits, grains, oil, salt, vegetables
b. fruits, grains, dairy, salt, vegetables
c. fruits, grains, protein, dairy, vegetables
d. grains, protein, dairy, oil, vegetables

Recovery heart rate is to determine how fast the heart recovers and should be measured five to ten minutes after vigorous activity. true or false

This migraine wont go away and i dont feel safe taking any more medicine for the next few hours

[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.