How does occurring in paired layers help the serous membrane perform its function?
A. Serous membranes need more epithelial layers than other kinds of membranes.
B. If one layer tears, the other can slide in place to protect an organ.
C. Two moist layers make it even easier for organs to move without friction.
D. One layer keeps pathogens in, while the other releases nutrients into the bloodstream.

Don recorded his food intake for a week and then used a computerized dietary analysis program to analyze his diet. according to the results of the analysis, his average daily saturated fat intake was 5% of total calories and his average daily unsaturated fat intake was 12% of total calories. based on this information, his total fat intake is the acceptable macronutrient distribution range.

[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.

What are the two things that all sociologists do in their studies?