Whay is the central idea of the "fact" respone​

The world’s richest 20 percent of the population consume about what percentage of all goods and services in a given year?

Which plan groups foods according to types and indicates how much of each type should be eaten daily for a healthy diet? a.mypyramid plan b.food guide pyramid plan c.dietary guidelines for americans d.dietary pyramid guidelines

[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.