Match each time period to the appropriate safety precaution related to mudslides. a. before a storm notice when the water levels of nearby creeks or streams begin to rise. b. during a storm find out the mudslide evacuation plans from local authorities. c. after a mudslide look for injured or trapped people.

[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.