Problem: The nucleotide sequence of a gene's DNA specifies the amino acid sequence of a protein through the genetic code. Sets of three nucleotides, known as codons, each correspond to a specific amino acid.:6 Additionally, a "start codon", and three "stop codons" indicate the beginning and end of the protein coding region. There are 64 possible codons (four possible nucleotides at each of three positions, hence 43 possible codons) and only 20 standard amino acids; hence the code is redundant and multiple codons can specify the same amino acid. The correspondence between codons and amino acids is nearly universal among all known living organisms.
What are sets of three nucleotides known as?
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Answer: codons

Problem: Where old disc recordings are considered to be of artistic or historic interest, from before the era of tape or where no tape master exists, archivists play back the disc on suitable equipment and record the result, typically onto a digital format, which can be copied and manipulated to remove analog flaws without any further damage to the source recording. For example, Nimbus Records uses a specially built horn record player to transfer 78s. Anyone can do this using a standard record player with a suitable pickup, a phono-preamp (pre-amplifier) and a typical personal computer. However, for accurate transfer, professional archivists carefully choose the correct stylus shape and diameter, tracking weight, equalisation curve and other playback parameters and use high-quality analogue-to-digital converters.
Is it difficult to transfer recording from historic interest to newer technologies?
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Answer: Anyone can do this

Problem: The playing time of a phonograph record depended on the turntable speed and the groove spacing. At the beginning of the 20th century, the early discs played for two minutes, the same as early cylinder records. The 12-inch disc, introduced by Victor in 1903, increased the playing time to three and a half minutes. Because a 10-inch 78 rpm record could hold about three minutes of sound per side and the 10-inch size was the standard size for popular music, almost all popular recordings were limited to around three minutes in length. For example, when King Oliver's Creole Jazz Band, including Louis Armstrong on his first recordings, recorded 13 sides at Gennett Records in Richmond, Indiana, in 1923, one side was 2:09 and four sides were 2:522:59.
How many recordings did Kind Oliver's Creole Jazz band require?
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Answer:
13