Problem: Alexander Graham Bell:

Bell believed the photophone's principles were his life's "greatest achievement", telling a reporter shortly before his death that the photophone was "the greatest invention [I have] ever made, greater than the telephone". The photophone was a precursor to the fiber-optic communication systems which achieved popular worldwide usage in the 1980s. Its master patent was issued in December 1880, many decades before the photophone's principles came into popular use.

What did Bell call the best thing he ever made?
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A: The photophone

Problem: The city has undergone many changes to its governance over the centuries and once again became administratively independent from Hampshire County as it was made into a unitary authority in a local government reorganisation on 1 April 1997, a result of the 1992 Local Government Act. The district remains part of the Hampshire ceremonial county.
What act was responsible for the reorganization of local government on April 1, 1997?
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Answer: 1992 Local Government Act

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
After Christianization, the Roman Catholic Church and local rulers led German expansion and settlement in areas inhabited by Slavs and Balts, known as Ostsiedlung. During the wars waged in the Baltic by the Catholic German Teutonic Knights; the lands inhabited by the ethnic group of the Old Prussians (the current reference to the people known then simply as the "Prussians"), were conquered by the Germans. The Old Prussians were an ethnic group related to the Latvian and Lithuanian Baltic peoples. The former German state of Prussia took its name from the Baltic Prussians, although it was led by Germans who had assimilated the Old Prussians; the old Prussian language was extinct by the 17th or early 18th century. The Slavic people of the Teutonic-controlled Baltic were assimilated into German culture and eventually there were many intermarriages of Slavic and German families, including amongst the Prussia's aristocracy known as the Junkers. Prussian military strategist Karl von Clausewitz is a famous German whose surname is of Slavic origin. Massive German settlement led to the assimilation of Baltic (Old Prussians) and Slavic (Wends) populations, who were exhausted by previous warfare.
Who is a famous German that name has Slavic origins?
A: Karl von Clausewitz

Context and question: The Duchy of Lancaster is one of two royal duchies in England. It has landholdings throughout the region and elsewhere, operating as a property company, but also exercising the right of the Crown in the County Palatine of Lancaster. While the administrative boundaries changed in the 1970s, the county palatine boundaries remain the same as the historic boundaries. As a result, the High Sheriffs for Lancashire, Greater Manchester and Merseyside are appointed "within the Duchy and County Palatine of Lancaster".
Who are appointed within the Duchy and County Palatine of Lancater?
Answer: High Sheriffs

Question: While successful predation results in a gain of energy, hunting invariably involves energetic costs as well. When hunger is not an issue, in general most predators will not seek to attack prey since the costs outweigh the benefits. For instance, a large predatory fish like a shark that is well fed in an aquarium will typically ignore the smaller fish swimming around it (while the prey fish take advantage of the fact that the apex predator is apparently uninterested). Surplus killing represents a deviation from this type of behaviour. The treatment of consumption in terms of cost-benefit analysis is known as optimal foraging theory, and has been quite successful in the study of animal behavior. In general, costs and benefits are considered in energy gain per unit time, though other factors are also important, such as essential nutrients that have no caloric value but are necessary for survival and health.
Is there an answer to this question: Treating the hunt as a cost-benefit scenario is referred to a what?

Answer: optimal foraging theory

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
IMF's forecast said that Greece's unemployment rate would hit the highest 14.8 percent in 2012 and decrease to 14.1 in 2014. But in fact, the Greek economy suffered a prolonged high unemployemnt. The unemployment figure was between 9 per cent and 11 per cent in 2009, and it soared to 28 per cent in 2013. In 2015, Greece's jobless rate is around 24 per cent. It is thought that Greece's potential output has been eroded by this prolonged massive unemployment due to the associated hysteresis effects.
What is thought to have eroded Greece's potential output?
A:
prolonged massive unemployment