Please answer this: Extract the answer to the question from the following context. Question: Which market did IBM enter first, PCs or cloud computing? Context: IBM has constantly evolved since its inception. Over the past decade, it has steadily shifted its business mix by exiting commoditizing markets such as PCs, hard disk drives and DRAMs and focusing on higher-value, more profitable markets such as business intelligence, data analytics, business continuity, security, cloud computing, virtualization and green solutions, resulting in a higher quality revenue stream and higher profit margins. IBM's operating margin expanded from 16.8% in 2004 to 24.3% in 2013, and net profit margins expanded from 9.0% in 2004 to 16.5% in 2013.
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Answer: PCs

Please answer this: Extract the answer to the question from the following context. Question: What does the regular water have that heavy water does not? Context: Hydrogen was liquefied for the first time by James Dewar in 1898 by using regenerative cooling and his invention, the vacuum flask. He produced solid hydrogen the next year. Deuterium was discovered in December 1931 by Harold Urey, and tritium was prepared in 1934 by Ernest Rutherford, Mark Oliphant, and Paul Harteck. Heavy water, which consists of deuterium in the place of regular hydrogen, was discovered by Urey's group in 1932. Francois Isaac de Rivaz built the first de Rivaz engine, an internal combustion engine powered by a mixture of hydrogen and oxygen in 1806. Edward Daniel Clarke invented the hydrogen gas blowpipe in 1819. The Dobereiner's lamp and limelight were invented in 1823.
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Answer: hydrogen

Please answer this: Extract the answer to the question from the following context. Question: The overhead wire method of powering streetcars was more unsightly than the conduit slot method, but it eventually overtook the slot method because it didn't have what downfalls? Context: Some street trams (streetcars) used conduit third-rail current collection. The third rail was below street level. The tram picked up the current through a plough (U.S. "plow") accessed through a narrow slot in the road. In the United States, much (though not all) of the former streetcar system in Washington, D.C. (discontinued in 1962) was operated in this manner to avoid the unsightly wires and poles associated with electric traction. The same was true with Manhattan's former streetcar system. The evidence of this mode of running can still be seen on the track down the slope on the northern access to the abandoned Kingsway Tramway Subway in central London, United Kingdom, where the slot between the running rails is clearly visible, and on P and Q Streets west of Wisconsin Avenue in the Georgetown neighborhood of Washington DC, where the abandoned tracks have not been paved over. The slot can easily be confused with the similar looking slot for cable trams/cars (in some cases, the conduit slot was originally a cable slot). The disadvantage of conduit collection included much higher initial installation costs, higher maintenance costs, and problems with leaves and snow getting in the slot. For this reason, in Washington, D.C. cars on some lines converted to overhead wire on leaving the city center, a worker in a "plough pit" disconnecting the plough while another raised the trolley pole (hitherto hooked down to the roof) to the overhead wire. In New York City for the same reasons of cost and operating efficiency outside of Manhattan overhead wire was used. A similar system of changeover from conduit to overhead wire was also used on the London tramways, notably on the southern side; a typical changeover point was at Norwood, where the conduit snaked sideways from between the running rails, to provide a park for detached shoes or ploughs.
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Answer:
higher initial installation costs, higher maintenance costs, and problems with leaves and snow getting in the slot