People who are lactose-intolerant

a. cannot break down the lactose found in milk.
b. cannot handle the protein, fats, minerals, and vitamins in milk.
c. can never eat anything that's made with a dairy ingredient.
d. are allergic to dairy.

What is one way in which an active listener can confirm understanding of a message?

Would you rather know how you die or when you die. i want a pretty good answer that makes sense. or ill report you. lol kidding

[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.