Love is the feeling of what? how can a person determine whether they are in love or not?

Trending data is needed when evaluating fitness levels in order to a. compare against others b. chart overall progress c. correct inaccurate data d. keep a person motivated

Iwill mark you brainlest if you answer this question

[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.