In order for a physical barrier to be effective in preventing infection, the barrier must . A. Prevent the substance from entering the body, trap the substance when it first enters the body, or flush the substance out of the body B. Destroy the substance before it enters the body, prevent the substance from reproducing, or flush the substance out of the body C. Trap the substance in the body, remove the substance from the body, or prevent the substance from reproducing D. Flush the substance from the body, transport the substance in the body, or destroy the substance in the body Please select the best answer from the choices provided. A B C D

Bulimia nervosa is characterized by a. a refusal to eat enough food to maintain normal, healthy body weight and/or the use of measures to produce severe weight loss. b. high fat intake and low level of physical activity. c. alternating binge eating and purging through vomiting, laxatives, or diuretics. d. normal food consumption interrupted by episodes of high consumption, resulting in obesity.

[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.

Traffic patterns refer to: how you move through a space hallways how rooms are connected to each other how rooms are organized