In twin studies it was found that if one member of a pair of identical twins abused alcohol the other abused it in ___% of cases. In a similar study of fraternal twins, if one twin abused alcohol the other abused it in ___% of cases.

Of these groups, which has the highest risk of being infected with HIV in America?

a) newborns whose mothers contract HIV after their births b) drug addicts who share hypodermic needles with other drug addicts c) restaurant workers who handle dishes that may be used by people with HIV d) hemophiliacs who need periodic blood transfusions, which are supplied by the Red Cross

Once they are infected with HIV, people are highly susceptible to

a) ulcers. b) heart disease. c) bone fractures. d) opportunistic infections.