Extract the answer to the question from the following context. Question: What is a variant reading? Context: When comparing different documents, or "witnesses", of a single, original text, the observed differences are called variant readings, or simply variants or readings. It is not always apparent which single variant represents the author's original work. The process of textual criticism seeks to explain how each variant may have entered the text, either by accident (duplication or omission) or intention (harmonization or censorship), as scribes or supervisors transmitted the original author's text by copying it. The textual critic's task, therefore, is to sort through the variants, eliminating those most likely to be un-original, hence establishing a "critical text", or critical edition, that is intended to best approximate the original. At the same time, the critical text should document variant readings, so the relation of extant witnesses to the reconstructed original is apparent to a reader of the critical edition. In establishing the critical text, the textual critic considers both "external" evidence (the age, provenance, and affiliation of each witness) and "internal" or "physical" considerations (what the author and scribes, or printers, were likely to have done).
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Answer: comparing different documents, or "witnesses", of a single, original text

Q: Extract the answer to the question from the following context. Question: What was the key material used to make the highest priced dye? Context: There were guilds of dyers who specialized in red in Venice and other large Europeans cities. The Rubia plant was used to make the most common dye; it produced an orange-red or brick red color used to dye the clothes of merchants and artisans. For the wealthy, the dye used was Kermes, made from a tiny scale insect which fed on the branches and leaves of the oak tree. For those with even more money there was Polish Cochineal; also known as Kermes vermilio or "Blood of Saint John", which was made from a related insect, the Margodes polonicus. It made a more vivid red than ordinary Kermes. The finest and most expensive variety of red made from insects was the "Kermes" of Armenia (Armenian cochineal, also known as Persian kirmiz), made by collecting and crushing Porphyophora hamelii, an insect which lived on the roots and stems of certain grasses. The pigment and dye merchants of Venice imported and sold all of these products and also manufactured their own color, called Venetian red, which was considered the most expensive and finest red in Europe. Its secret ingredient was arsenic, which brightened the color.
A: arsenic

Question: Extract the answer to the question from the following context. Question: who bitterly attacked Huxley, Hooker and Darwin? Context: The leading naturalist in Britain was the anatomist Richard Owen, an idealist who had shifted to the view in the 1850s that the history of life was the gradual unfolding of a divine plan. Owen's review of the Origin in the April 1860 Edinburgh Review bitterly attacked Huxley, Hooker and Darwin, but also signalled acceptance of a kind of evolution as a teleological plan in a continuous "ordained becoming", with new species appearing by natural birth. Others that rejected natural selection, but supported "creation by birth", included the Duke of Argyll who explained beauty in plumage by design. Since 1858, Huxley had emphasised anatomical similarities between apes and humans, contesting Owen's view that humans were a separate sub-class. Their disagreement over human origins came to the fore at the British Association for the Advancement of Science meeting featuring the legendary 1860 Oxford evolution debate. In two years of acrimonious public dispute that Charles Kingsley satirised as the "Great Hippocampus Question" and parodied in The Water-Babies as the "great hippopotamus test", Huxley showed that Owen was incorrect in asserting that ape brains lacked a structure present in human brains. Others, including Charles Lyell and Alfred Russel Wallace, thought that humans shared a common ancestor with apes, but higher mental faculties could not have evolved through a purely material process. Darwin published his own explanation in the Descent of Man (1871).
Answer: Owen

[Q]: Extract the answer to the question from the following context. Question: Who helped Brezhnev? Context: Between October 1416, 1964, Leonid Brezhnev and a small cadre of high-ranking Communist Party officials, deposed Khrushchev as Soviet government leader a day after Voskhod 1 landed, in what was called the "Wednesday conspiracy". The new political leaders, along with Korolev, ended the technologically troublesome Voskhod program, cancelling Voskhod 3 and 4, which were in the planning stages, and started concentrating on the race to the Moon. Voskhod 2 would end up being Korolev's final achievement before his death on January 14, 1966, as it would become the last of the many space firsts that demonstrated the USSR's domination in spacecraft technology during the early 1960s. According to historian Asif Siddiqi, Korolev's accomplishments marked "the absolute zenith of the Soviet space program, one never, ever attained since." There would be a two-year pause in Soviet piloted space flights while Voskhod's replacement, the Soyuz spacecraft, was designed and developed.
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[A]: a small cadre of high-ranking Communist Party officials

input: Please answer the following: Extract the answer to the question from the following context. Question: What can you find in a library? Context: Nanjing Library, founded in 1907, houses more than 10 million volumes of printed materials and is the third largest library in China, after the National Library in Beijing and Shanghai Library. Other libraries, such as city-owned Jinling Library and various district libraries, also provide considerable amount of information to citizens. Nanjing University Library is the second largest university libraries in China after Peking University Library, and the fifth largest nationwide, especially in the number of precious collections.
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output: printed materials

Extract the answer to the question from the following context. Question: Why did Bell make one of the first metal detectors? Context: Bell is also credited with developing one of the early versions of a metal detector in 1881. The device was quickly put together in an attempt to find the bullet in the body of U.S. President James Garfield. According to some accounts, the metal detector worked flawlessly in tests but did not find the assassin's bullet partly because the metal bed frame on which the President was lying disturbed the instrument, resulting in static. The president's surgeons, who were skeptical of the device, ignored Bell's requests to move the president to a bed not fitted with metal springs. Alternatively, although Bell had detected a slight sound on his first test, the bullet may have been lodged too deeply to be detected by the crude apparatus.
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Answer:
in an attempt to find the bullet in the body of U.S. President James Garfield