Problem: Valencia:

During the 20th century Valencia remained the third most populous city of Spain as its population tripled, rising from 213,550 inhabitants in 1900 to 739,014 in 2000. Valencia was also third in industrial and economic development; notable milestones include urban expansion of the city in the latter 1800s, the creation of the Banco de Valencia in 1900, construction of the Central and Columbus markets, and the construction of the Gare du Nord railway station, completed in 1921. The new century was marked in Valencia with a major event, the Valencian regional exhibition of 1909 (La Exposición Regional Valenciana de 1909), which emulated the national and universal expositions held in other cities. This production was promoted by the Ateneo Mercantil de Valencia (Mercantile Athenaeum of Valencia), especially by its chairman, Tomás Trénor y Palavicino, and had the support of the Government and the Crown; it was officially inaugurated by King Alfonso XIII himself.

When was the Valencian regional exhibition held?
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A: 1909


Problem: Early progress toward the development of vaccines occurred throughout this period, primarily in the form of academic and government-funded basic research directed toward the identification of the pathogens responsible for common communicable diseases. In 1885 Louis Pasteur and Pierre Paul Émile Roux created the first rabies vaccine. The first diphtheria vaccines were produced in 1914 from a mixture of diphtheria toxin and antitoxin (produced from the serum of an inoculated animal), but the safety of the inoculation was marginal and it was not widely used. The United States recorded 206,000 cases of diphtheria in 1921 resulting in 15,520 deaths. In 1923 parallel efforts by Gaston Ramon at the Pasteur Institute and Alexander Glenny at the Wellcome Research Laboratories (later part of GlaxoSmithKline) led to the discovery that a safer vaccine could be produced by treating diphtheria toxin with formaldehyde. In 1944, Maurice Hilleman of Squibb Pharmaceuticals developed the first vaccine against Japanese encephelitis. Hilleman would later move to Merck where he would play a key role in the development of vaccines against measles, mumps, chickenpox, rubella, hepatitis A, hepatitis B, and meningitis.
What compound made the diphtheria vaccine safer to use?
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Answer: formaldehyde


Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
The British Isles lie at the juncture of several regions with past episodes of tectonic mountain building. These orogenic belts form a complex geology that records a huge and varied span of Earth's history. Of particular note was the Caledonian Orogeny during the Ordovician Period, c. 488–444 Ma and early Silurian period, when the craton Baltica collided with the terrane Avalonia to form the mountains and hills in northern Britain and Ireland. Baltica formed roughly the northwestern half of Ireland and Scotland. Further collisions caused the Variscan orogeny in the Devonian and Carboniferous periods, forming the hills of Munster, southwest England, and southern Wales. Over the last 500 million years the land that forms the islands has drifted northwest from around 30°S, crossing the equator around 370 million years ago to reach its present northern latitude.
What formed before the craton Baltica and Avalonia collision?
A: unanswerable


Context and question: Agriculture is dominated by the cultivation and sale of food crops such as cassava, peanuts, maize, sorghum, millet, sesame, and plantain. The annual real GDP growth rate is just above 3%. The importance of food crops over exported cash crops is indicated by the fact that the total production of cassava, the staple food of most Central Africans, ranges between 200,000 and 300,000 tonnes a year, while the production of cotton, the principal exported cash crop, ranges from 25,000 to 45,000 tonnes a year. Food crops are not exported in large quantities, but still constitute the principal cash crops of the country, because Central Africans derive far more income from the periodic sale of surplus food crops than from exported cash crops such as cotton or coffee.[citation needed] Much of the country is self-sufficient in food crops; however, livestock development is hindered by the presence of the tsetse fly.[citation needed]
What product is produced that is exported?
Answer: cotton


Question: Mercury has been smelted from cinnabar for thousands of years. Mercury dissolves many metals, such as gold, silver, and tin, to form amalgams (an alloy in a soft paste, or liquid form at ambient temperature). Amalgams have been used since 200 BC in China for plating objects with precious metals, called gilding, such as armor and mirrors. The ancient Romans often used mercury-tin amalgams for gilding their armor. The amalgam was applied as a paste and then heated until the mercury vaporized, leaving the gold, silver, or tin behind. Mercury was often used in mining, to extract precious metals like gold and silver from their ores.
Is there an answer to this question: What is used to plate objects with common metals?

Answer: unanswerable


Question: In its 2014 Press Freedom Index, Reporters Without Borders ranked the media environment in Eritrea at the very bottom of a list of 178 countries, just below totalitarian North Korea. According to the BBC, "Eritrea is the only African country to have no privately owned news media", and Reporters Without Borders said of the public media, "[they] do nothing but relay the regime's belligerent and ultra-nationalist discourse. ... Not a single [foreign correspondent] now lives in Asmara." The state-owned news agency censors news about external events. Independent media have been banned since 2001. In 2015, The Guardian published an opinion piece claiming,
Is there an answer to this question: According to Reporters Without Borders, where doesn't a single foreign news correspondent live?

Answer:
Asmara