How would the effects of a collagen vascular disease that affects only the collagen in reticular fibers differ from the effects? why? \?

[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.

When a freind is not tellig you everything you should a: bug them till they tell you b: ask them polietly to tell you c; stay silent your whole life d leave them they will tell you on there own time

Christopher came down with chicken pox after spending time in his child’s day care. the chicken pox represents what link in the chain of transmission in this scenario?