The ability of the cardiovascular and respiratory systems to efficiently transfer oxygen and nutrients to skeletal muscles is known as:
endurance
cardiorespiratory fitness
muscular fitness
composition

[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.

*edit* i took the test and i picked a and it was incorrect for its c! rank the following suggestions for preventing std, in order of increasing effectiveness. 1) using latex condoms properly 2) using spermicidal foam or jelly with a monogamous partner 3) abstaining from sexual intercourse and genital contact a. 1, 2, 3c. 2, 1, 3

Which of these is a sexual stereotype? a) on average, males are taller than females. b) people over the age of 60 are not interested in sex. c) male hormone levels differ from those of females. d) there are more male representatives than female representatives in congress.