Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
Hydroelectricity is the term referring to electricity generated by hydropower; the production of electrical power through the use of the gravitational force of falling or flowing water. It is the most widely used form of renewable energy, accounting for 16 percent of global electricity generation 3,427 terawatt-hours of electricity production in 2010, and is expected to increase about 3.1% each year for the next 25 years. Hydroelectric plants have the advantage of being long-lived and many existing plants have operated for more than 100 years.
What is the most widely used form of renewable energy?
A: Hydroelectricity

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
England failed to qualify for the World Cup in 1974, 1978 and 1994. The team's earliest exit in the competition itself was its elimination in the first round in 1950, 1958 and most recently in the 2014 FIFA World Cup, after being defeated in both their opening two matches for the first time, versus Italy and Uruguay in Group D. In 1950, four teams remained after the first round, in 1958 eight teams remained and in 2014 sixteen teams remained. In 2010, England suffered its most resounding World Cup defeat (41 to Germany) in the Round of 16, after drawing with the United States and Algeria and defeating Slovenia 10 in the group stage.
In what year was Germany's football team's worst defeat?
A: unanswerable

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
The last great period of Roman mosaic art was the 12th13th century when Rome developed its own distinctive artistic style, free from the strict rules of eastern tradition and with a more realistic portrayal of figures in the space. Well-known works of this period are the floral mosaics of the Basilica di San Clemente, the facade of Santa Maria in Trastevere and San Paolo fuori le Mura. The beautiful apse mosaic of Santa Maria in Trastevere (1140) depicts Christ and Mary sitting next to each other on the heavenly throne, the first example of this iconographic scheme. A similar mosaic, the Coronation of the Virgin, decorates the apse of Santa Maria Maggiore. It is a work of Jacopo Torriti from 1295. The mosaics of Torriti and Jacopo da Camerino in the apse of San Giovanni in Laterano from 128894 were thoroughly restored in 1884. The apse mosaic of San Crisogono is attributed to Pietro Cavallini, the greatest Roman painter of the 13th century. Six scenes from the life of Mary in Santa Maria in Trastevere were also executed by Cavallini in 1290. These mosaics are praised for their realistic portrayal and attempts of perspective. There is an interesting mosaic medaillon from 1210 above the gate of the church of San Tommaso in Formis showing Christ enthroned between a white and a black slave. The church belonged to the Order of the Trinitarians which was devoted to ransoming Christian slaves.
What year was the medallion above the gate of the church of San Tommaso?
A: 1210

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
In Northern Germany, Netherlands, northern Poland, Denmark, and the Baltic countries local building stone was unavailable but there was a strong tradition of building in brick. The resultant style, Brick Gothic, is called "Backsteingotik" in Germany and Scandinavia and is associated with the Hanseatic League. In Italy, stone was used for fortifications, but brick was preferred for other buildings. Because of the extensive and varied deposits of marble, many buildings were faced in marble, or were left with undecorated facade so that this might be achieved at a later date.
Why were many buildings covered with marbles?
A:
unanswerable