The problem: Answer a question about this article:
The Compact Disc is an evolution of LaserDisc technology, where a focused laser beam is used that enables the high information density required for high-quality digital audio signals. Prototypes were developed by Philips and Sony independently in the late 1970s. In 1979, Sony and Philips set up a joint task force of engineers to design a new digital audio disc. After a year of experimentation and discussion, the Red Book CD-DA standard was published in 1980. After their commercial release in 1982, compact discs and their players were extremely popular. Despite costing up to $1,000, over 400,000 CD players were sold in the United States between 1983 and 1984. The success of the compact disc has been credited to the cooperation between Philips and Sony, who came together to agree upon and develop compatible hardware. The unified design of the compact disc allowed consumers to purchase any disc or player from any company, and allowed the CD to dominate the at-home music market unchallenged.
Who created Compact Disc prototypes in the 1970s?
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The answer: Philips and Sony


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With the defeat of Marshal Bazaine's Army of the Rhine at Gravelotte, the French were forced to retire to Metz, where they were besieged by over 150,000 Prussian troops of the First and Second Armies. Napoleon III and MacMahon formed the new French Army of Châlons, to march on to Metz to rescue Bazaine. Napoleon III personally led the army with Marshal MacMahon in attendance. The Army of Châlons marched northeast towards the Belgian border to avoid the Prussians before striking south to link up with Bazaine. The Prussians, under the command of Field Marshal Count Helmuth von Moltke, took advantage of this maneuver to catch the French in a pincer grip. He left the Prussian First and Second Armies besieging Metz, except three corps detached to form the Army of the Meuse under the Crown Prince of Saxony. With this army and the Prussian Third Army, Moltke marched northward and caught up with the French at Beaumont on 30 August. After a sharp fight in which they lost 5,000 men and 40 cannons, the French withdrew toward Sedan. Having reformed in the town, the Army of Châlons was immediately isolated by the converging Prussian armies. Napoleon III ordered the army to break out of the encirclement immediately. With MacMahon wounded on the previous day, General Auguste Ducrot took command of the French troops in the field.
What factor forced the French to retreat to Metz?
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The answer: the defeat of Marshal Bazaine's Army


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Another residence was maintained at Lake Bled, while the grounds at Karađorđevo were the site of "diplomatic hunts". By 1974 the Yugoslav President had at his disposal 32 official residences, larger and small, the yacht Galeb ("seagull"), a Boeing 727 as the presidential airplane, and the Blue Train. After Tito's death the presidential Boeing 727 was sold to Aviogenex, the Galeb remained docked in Montenegro, while the Blue Train was stored in a Serbian train shed for over two decades. While Tito was the person who held the office of president for by far the longest period, the associated property was not private and much of it continues to be in use by Yugoslav successor states, as public property, or maintained at the disposal of high-ranking officials.
What is the English translation of Galeb?
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The answer: seagull


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Kolmaš writes that, as the Mongol presence in Tibet increased, culminating in the conquest of Tibet by a Mongol leader in 1642, the Ming emperors "viewed with apparent unconcern these developments in Tibet." He adds that the Ming court's lack of concern for Tibet was one of the reasons why the Mongols pounced on the chance to reclaim their old vassal of Tibet and "fill once more the political vacuum in that country." On the mass Mongol conversion to Tibetan Buddhism under Altan Khan, Laird writes that "the Chinese watched these developments with interest, though few Chinese ever became devout Tibetan Buddhists."
What were the Mongols trying to reclaim?
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The answer:
their old vassal of Tibet