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In this task, you're given an article and an answer. Your task is to generate the question for the answer based on the given article.

Article: There are a lot of public libraries in Britain. These libraries have more than one hundred and fifteen million books, not including those libraries of public schools. Public libraries not only lend books, music records but also help children, patients in hospitals and others to get special play readings, film shows and so on. The first public libraries were founded in about the year 1850. Today's public libraries usually have a reading-room, a lending room and a reference room. The greatest and most famous library in Britain is that of the British Library in London. It was founded in 1973 and has over 10, 000, 000 books. It has nearly every magazine, newspaper and book published in Britain and other parts across the world.
Answer: 10,000,000 or less.
Solution: How many books are there in the British Library?
Why? In the Article, 10,000,000 is mentioned for the number of books available in the British Library, so this is a good question.

New input: Article: To many web-building spiders, most of whom are nearly blind, the web is their essential window on the world: their means of communicating, capturing prey, meeting mates and protecting themselves. A web-building spider without its web is like a men cast away on an island of solid rock,totally out of touch and destined to starve to death. So important is the web to an orb-web spider's survival that the animal will continue to construct new webs daily even if it is being starved. For 16 days the starving spider builds completely normal webs. Then, as the animal gets _ , it constructs a wider-meshed (, )web using fewer strands . Such webs would only trap larger prey, which is more economical from the perspective of a starving spider. The spider stores energy by recycling web protein. It simply eats its own web each evening and reuses it to produce new silk. In studies with radioactivity, labeled materials, it was found that 95 percent of web protein reappears in the next day web. Most of the energy needed for web-building is used in walking over the strands as they are laid down. Scientists are impressed by the adaptability of the spider's highly preprogrammed brain, which is larger for its size than the brain of any other invertebrate . If web-building is interrupted, or if some of the existing strands are destroyed, the spider simply goes back to see where the web is left off and then finishes building a normal web. One spider will finish building the incomplete web of another.
Answer: Importance of Webs to Spiders
Solution:
Which of the following best expresses the main ideas of the passage?