Copying from Wikipedia to make a book is fair game, with a few minor caveats. (See related link for the Wikipedia copyrights details, the primary exception is that their license covers content produced by Wikipedia but not necessarily content quoted from a third party.)
In brief, anyone can use Wikipedia content for anything (with a few exceptions, see the related link) if
The world would collapse.
You would know. That means you copied someone else's work & took credit for it.
Wikipedia would be a good place for someone to find information on the phylogeny of butterflies. Wikipedia is a free encyclopedia with wonderful information on butterflies.
You would get a photo of your hand. Other than that, not much if you only did it once or twice. It would be kind of like keeping a laptop on your lap.
Either have copied somethig outright that someone else had done, or written something that's so close that it looks like it's been copied.
No. I am sure she did, however, read numerous vampire books before writing the Twilight series, and these may have been her inspiration. She may have taken old ideas (Vampire Diaries was written in early 90s) and revamped them (no pun intended.) If she had copied someone else's book, that would be plagiarism, and the person whose book she copied would probably sue.
Someone would have to invent them
It happens because how would you feel if someone copied you well if you don't care well some people do.
Unfortunately, the Wikipedia articles that are on Answers.com (on the ReferenceAnswers side, not the WikiAnswers side) are exact copies of the Wikipedia articles, and they update almost as fast. It wouldn't do any good to edit it only on the ReferenceAnswers side, because any edit would only be copied over when we got the next update from Wikipedia.
You get a deficiency disease known as scurvy. You can read about it in Wikipedia.
Someone would be screaming in pain.
they would have to go to court