Problem: Hydrogen is employed to saturate broken ("dangling") bonds of amorphous silicon and amorphous carbon that helps stabilizing material properties. It is also a potential electron donor in various oxide materials, including ZnO, SnO2, CdO, MgO, ZrO2, HfO2, La2O3, Y2O3, TiO2, SrTiO3, LaAlO3, SiO2, Al2O3, ZrSiO4, HfSiO4, and SrZrO3.
Why is hydrogen employed?
The answer is the following: to saturate broken ("dangling") bonds of amorphous silicon and amorphous carbon that helps stabilizing material properties

Problem: These ongoing efforts contributed to the formation of The Football Association (The FA) in 1863, which first met on the morning of 26 October 1863 at the Freemasons' Tavern in Great Queen Street, London. The only school to be represented on this occasion was Charterhouse. The Freemason's Tavern was the setting for five more meetings between October and December, which eventually produced the first comprehensive set of rules. At the final meeting, the first FA treasurer, the representative from Blackheath, withdrew his club from the FA over the removal of two draft rules at the previous meeting: the first allowed for running with the ball in hand; the second for obstructing such a run by hacking (kicking an opponent in the shins), tripping and holding. Other English rugby clubs followed this lead and did not join the FA and instead in 1871 formed the Rugby Football Union. The eleven remaining clubs, under the charge of Ebenezer Cobb Morley, went on to ratify the original thirteen laws of the game. These rules included handling of the ball by "marks" and the lack of a crossbar, rules which made it remarkably similar to Victorian rules football being developed at that time in Australia. The Sheffield FA played by its own rules until the 1870s with the FA absorbing some of its rules until there was little difference between the games.
What year did the Football Association form?
The answer is the following: 1863

Problem: Following his victory in the Battle of Hastings, William, Duke of Normandy, was crowned King of England in the newly finished Westminster Abbey on Christmas Day 1066. William constructed the Tower of London, the first of the many Norman castles in England to be rebuilt in stone, in the southeastern corner of the city, to intimidate the native inhabitants. In 1097, William II began the building of Westminster Hall, close by the abbey of the same name. The hall became the basis of a new Palace of Westminster.
Who built Westminster Hall?
The answer is the following: William II

Problem: High levels of precipitation cause the glaciers to descend to permafrost levels in some areas whereas in other, more arid regions, glaciers remain above about the 3,500 m (11,483 ft) level. The 1,817 square kilometres (702 sq mi) of the Alps covered by glaciers in 1876 had shrunk to 1,342 km2 (518 sq mi) by 1973, resulting in decreased river run-off levels. Forty percent of the glaciation in Austria has disappeared since 1850, and 30% of that in Switzerland.
How much of the glaciation disappeared in Switzerland?
The answer is the following:
30%