Cotton candy was invented by a dentist.
Why it is true
William Morrison, a dentist, co-invented cotton candy in 1897 with confectioner John Wharton.
Source: Food History
Would you rather be asked first?
This is the reading side of the site, so the answer is in the sentence above — that is the whole point of it. Test yourself works the other way round: the question comes on its own, and the fact and the explanation only appear once you have answered.