The word CAPTCHA is actually a complex acronym.
Why it is true
It stands for Completely Automated Public Turing test to tell Computers and Humans Apart, used to prevent bots from accessing websites or creating fake accounts.
Source: Internet Security
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.