An individual center of gravity can usually be found a. just above the belly button b. just above the knees c. just below the neck d. just below the hips

In some states the highway patrol use plane carrying radar device5s to monitor traffic as the plane flies over traffic the radar device can tell the officers how fast each car is moving at the moment in time the radar device determines the cars

Which of these is most likely to prevent pregnancy? a. tracking of female body temperature to identify ovulation times b. proper condom use c. male withdrawal before ejaculation d. proper spermicide use

[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.