[Q]: Question: "If there is atmospheric oxygen present, we know that there cannot be what?" Context: "In the absence of atmospheric oxygen (O2), in deep geological conditions prevailing far away from Earth atmosphere, hydrogen (H2) is produced during the process of serpentinization by the anaerobic oxidation by the water protons (H+) of the ferrous (Fe2+) silicate present in the crystal lattice of the fayalite (Fe2SiO4, the olivine iron-endmember). The corresponding reaction leading to the formation of magnetite (Fe3O4), quartz (SiO2) and hydrogen (H2) is the following:" Answer:
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[A]: hydrogen (H2)

[Q]: Question: "What happened to the compeer to the sole purveyor of news to the majority of people in the fourth most populous urban settlement in the United States near the end of the 20th Century?" Context: "Houston is served by the Houston Chronicle, its only major daily newspaper with wide distribution. The Hearst Corporation, which owns and operates the Houston Chronicle, bought the assets of the Houston Postits long-time rival and main competitionwhen Houston Post ceased operations in 1995. The Houston Post was owned by the family of former Lieutenant Governor Bill Hobby of Houston. The only other major publication to serve the city is the Houston Pressa free alternative weekly with a weekly readership of more than 300,000." Answer:
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[A]: ceased operations

[Q]: Question: "These vehicles are located in?" Context: "Israel has 18,096 kilometers (11,244 mi) of paved roads, and 2.4 million motor vehicles. The number of motor vehicles per 1,000 persons was 324, relatively low with respect to developed countries. Israel has 5,715 buses on scheduled routes, operated by several carriers, the largest of which is Egged, serving most of the country. Railways stretch across 949 kilometers (590 mi) and are operated solely by government-owned Israel Railways (All figures are for 2008). Following major investments beginning in the early to mid-1990s, the number of train passengers per year has grown from 2.5 million in 1990, to 35 million in 2008; railways are also used to transport 6.8 million tons of cargo, per year." Answer:
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[A]: Israel

[Q]: Question: "What about the Aryan's grew?" Context: "At the end of the Rigvedic period, the Aryan society began to expand from the northwestern region of the Indian subcontinent, into the western Ganges plain. It became increasingly agricultural and was socially organised around the hierarchy of the four varnas, or social classes. This social structure was characterized both by syncretising with the native cultures of northern India, but also eventually by the excluding of indigenous peoples by labelling their occupations impure. During this period, many of the previous small tribal units and chiefdoms began to coalesce into monarchical, state-level polities." Answer:
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[A]:
society