Which statement accurately describes the ingumentary system A. It's the body's second line of defense against infection B. it's the body's third line of defense against infection C. It does not defend the body from infection D. It's the body's first line of defense against infection

[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.

Absorption of food occurs in the small intestines true or false

Muscles of the body for seventh grade