Supplements are
a. only prescribed by a doctor.
b. required to show scientific evidence of effectiveness.
c. regulated and must be approved by the fda.
d. products such as vitamins, diet pills, protein powders, and others.

*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