Question 2
Gonorrhoea and syphilis can be cured, while herpes and AIDS cannot. What explains the difference?
The right answer is the one marked above.
The first two are caused by bacteria, which medicines act on; the others are caused by viruses. It is the one fact that predicts everything else about these four diseases.
Untreated gonorrhoea causes blindness and lameness, so it is not the milder disease — and untreated syphilis spreads through the whole body. Herpes, though incurable, is not fatal. Severity and curability are separate things here.