Problem: Hydrogen:

Large quantities of H
2 are needed in the petroleum and chemical industries. The largest application of H
2 is for the processing ("upgrading") of fossil fuels, and in the production of ammonia. The key consumers of H
2 in the petrochemical plant include hydrodealkylation, hydrodesulfurization, and hydrocracking. H
2 has several other important uses. H
2 is used as a hydrogenating agent, particularly in increasing the level of saturation of unsaturated fats and oils (found in items such as margarine), and in the production of methanol. It is similarly the source of hydrogen in the manufacture of hydrochloric acid. H
2 is also used as a reducing agent of metallic ores.

Where are large quantities of H2 needed?
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A: petroleum and chemical industries

Problem: Regular flights to most villages and towns within the state that are commercially viable are challenging to provide, so they are heavily subsidized by the federal government through the Essential Air Service program. Alaska Airlines is the only major airline offering in-state travel with jet service (sometimes in combination cargo and passenger Boeing 737-400s) from Anchorage and Fairbanks to regional hubs like Bethel, Nome, Kotzebue, Dillingham, Kodiak, and other larger communities as well as to major Southeast and Alaska Peninsula communities.
Which airline offers in-state travel with jet-service?
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Answer: Alaska Airlines

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
Changes also took place within the recruitment and composition of armies. The use of the national or feudal levy was gradually replaced by paid troops of domestic retinues or foreign mercenaries. The practice was associated with Edward III of England and the condottieri of the Italian city-states. All over Europe, Swiss soldiers were in particularly high demand. At the same time, the period also saw the emergence of the first permanent armies. It was in Valois France, under the heavy demands of the Hundred Years' War, that the armed forces gradually assumed a permanent nature.
Which conflict in France resulted in the abolishment of permanent armies?
A: unanswerable

Context and question: Estonian belongs to the Finnic branch of the Uralic languages, along with Finnish, Karelian, and other nearby languages. The Uralic languages do not belong to the Indo-European languages. Estonian is distantly related to Hungarian and to the Sami languages.
What Uralic language branch does not contain Estonian?
Answer: unanswerable

Question: Gram quantities of various copper salts have been taken in suicide attempts and produced acute copper toxicity in humans, possibly due to redox cycling and the generation of reactive oxygen species that damage DNA. Corresponding amounts of copper salts (30 mg/kg) are toxic in animals. A minimum dietary value for healthy growth in rabbits has been reported to be at least 3 ppm in the diet. However, higher concentrations of copper (100 ppm, 200 ppm, or 500 ppm) in the diet of rabbits may favorably influence feed conversion efficiency, growth rates, and carcass dressing percentages.
Is there an answer to this question: What is the minimum amount of copper rabbits should have in their diet?

Answer: 3 ppm

Problem: Great power:

Referring to great power relations pre-1960, Joshua Baron highlights that starting from around the 16th century and the rise of several European great powers, military conflicts and confrontations was the defining characteristic of diplomacy and relations between such powers. "Between 1500 and 1953, there were 64 wars in which at least one great power was opposed to another, and they averaged little more than five years in length. In approximately a 450-year time frame, on average at least two great powers were fighting one another in each and every year." Even during the period of Pax Britannica (or "the British Peace") between 1815 and 1914, war and military confrontations among the great powers was still a frequent occurrence. In fact, Joshua Baron points out that, in terms of militarized conflicts or confrontations, the UK led the way in this period with nineteen such instances against; Russia (8), France (5), Germany/Prussia (5) and Italy (1).

During what time frame was diplomacy frequent among the great powers?
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A:
unanswerable