Question

Edward Jenner discovered a vaccination against ______ by infecting a boy with _____.

measles; smallpox
cowpox; smallpox
polio; cowpox
smallpox; cowpox

Answer 1

The correct answer is the last option: smallpox; cowpox

Answer 2

Edward Jenner discovered a vaccination against [smallpox] by infecting a boy with [cowpox]. He noticed that milkmaids who got cowpox never got smallpox and developed his theory from there. He is the father of the study of immunity and immunisation.