Thomas jefferson suggested to lewis and clark that they teach the native americans to inoculate themselves against what disease?
a. smallpox
b. measles
c. chicken pox

Which of the following  bestillustrates a negative reinforcer?               a.  copland gives up candy to stave off chronic acid indigestion.    b.  nancy learns that she prefers chocolate over vanilla.    c.  carmine changes his major to english lit after failing a math exam.    d.  on a hot day, lindberg always drinks lemonade.