Problem: As in the Scheiner system, speeds were expressed in 'degrees'. Originally the sensitivity was written as a fraction with 'tenths' (for example "18/10 DIN"), where the resultant value 1.8 represented the relative base 10 logarithm of the speed. 'Tenths' were later abandoned with DIN 4512:1957-11, and the example above would be written as "18 DIN". The degree symbol was finally dropped with DIN 4512:1961-10. This revision also saw significant changes in the definition of film speeds in order to accommodate then-recent changes in the American ASA PH2.5-1960 standard, so that film speeds of black-and-white negative film effectively would become doubled, that is, a film previously marked as "18 DIN" would now be labeled as "21 DIN" without emulsion changes.
What happened to film speeds of black-and-white negative film?
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Answer: would become doubled

Problem: Some of Chopin's well-known pieces have acquired descriptive titles, such as the Revolutionary Etude (Op. 10, No. 12), and the Minute Waltz (Op. 64, No. 1). However, with the exception of his Funeral March, the composer never named an instrumental work beyond genre and number, leaving all potential extramusical associations to the listener; the names by which many of his pieces are known were invented by others. There is no evidence to suggest that the Revolutionary Etude was written with the failed Polish uprising against Russia in mind; it merely appeared at that time. The Funeral March, the third movement of his Sonata No. 2 (Op. 35), the one case where he did give a title, was written before the rest of the sonata, but no specific event or death is known to have inspired it.
The Funeral March was written as part of what piece?
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Answer: Sonata No. 2

Problem: The development of a three-field rotation system for planting crops[AA] increased the usage of land from one half in use each year under the old two-field system to two-thirds under the new system, with a consequent increase in production. The development of the heavy plough allowed heavier soils to be farmed more efficiently, aided by the spread of the horse collar, which led to the use of draught horses in place of oxen. Horses are faster than oxen and require less pasture, factors that aided the implementation of the three-field system.
What invention led to an increase in efficiency in the farming of heavy soils?
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Answer:
the heavy plough