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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: Walk through the Amazon rainforest today and you will find it steamy, warm, damp and thick. But if you had been there around 15,000 years ago, during the last ice age, would it have been the same? For more than 30 years, scientists have been arguing about how rainforests might have reacted to the cold, dry climate of the ice ages, but till now, no one has reached a satisfying answer. Rainforests like the Amazon are important for mopping up CO2 from the atmosphere and helping to solve global warming. Currently the trees in the Amazon take in around 500 million tons of CO2 each year: equal to the total amount of CO2 given off in the UK each year. But how will the Amazon react to the future climate change? If it gets drier, will it survive and continue to draw down CO2? Scientists hope that they will be able to learn in advance how the rainforest will manage in the future by understanding how rainforests reacted to climate change in the past. Unfortunately, collecting information is incredibly difficult. To study the past climate, scientists need to look at fossilized pollen kept in lake mud, Going back to the last ice age means drilling down into lake sediments , which requires specialized equipment and heavy machinery. There are very few roads and paths, or places to land helicopters and aeroplanes. Rivers tend to be the easiest way to enter the forest, but this still leaves vast areas between the rivers completely unsampled . So far, only a handful of cores have been drilled that go back to the last ice age and none of them provide enough information to prove how the Amazon forest reacts to climate change.
Answer: By taking samples from rivers in the Amazon.
Solution:
How do scientists study the past climate change?