dkoterwa/mlqa_filtered huggingface dataset:
The population decrease was also a result of the Croatian War of Independence. During the war, large sections of the population were displaced and emigration increased. In 1991, in predominantly occupied  areas, more than 400,000 Croats were either removed from their homes by the Croatian Serb forces or fled the violence. During the final days of the war in 1995, more than 100,000 Serbs voluntarily fled the country before the arrival of Croatian forces during Operation Storm to avoid being brought to justice for their unjustifiable acts committed during the Croatian War for Independence. After the war, the number of displaced persons fell to about 250,000. The Croatian government has taken care of displaced persons by the social security system, and since December 1991 through the Office of Displaced Persons and Refugees.Most of the territories which were abandoned during the Croatian War of Independence were settled by Croat refugees from Bosnia and Herzegovina, mostly from north-western Bosnia, while some of the displaced people returned to their homes.According to the 2013 United Nations report, 17.6% of Croatia's population were foreign-born immigrants. Croatia is inhabited mostly by Croats (90.4%) and is ethnically the most homogeneous of the six countries of former Yugoslavia. Minority groups include Serbs (4.4%), Bosniaks, Italians, Albanians, Roma, Hungarians, Slovenes, Czechs, Montenegrins, Macedonians, Yugoslavs, and others (1.98%).

Question: Who removed the Croats?
Answer: Croatian Serb forces
Optical theory progressed in the mid-17th century with treatises written by philosopher René Descartes, which explained a variety of optical phenomena including reflection and refraction by assuming that light was emitted by objects which produced it. This differed substantively from the ancient Greek emission theory. In the late 1660s and early 1670s, Isaac Newton expanded Descartes' ideas into a corpuscle theory of light, famously determining that white light was a mix of colours which can be separated into its component parts with a prism. In 1690, Christiaan Huygens proposed a wave theory for light based on suggestions that had been made by Robert Hooke in 1664. Hooke himself publicly criticised Newton's theories of light and the feud between the two lasted until Hooke's death. In 1704, Newton published Opticks and, at the time, partly because of his success in other areas of physics, he was generally considered to be the victor in the debate over the nature of light.Newtonian optics was generally accepted until the early 19th century when Thomas Young and Augustin-Jean Fresnel conducted experiments on the interference of light that firmly established light's wave nature. Young's famous double slit experiment showed that light followed the law of superposition, which is a wave-like property not predicted by Newton's corpuscle theory. This work led to a theory of diffraction for light and opened an entire area of study in physical optics. Wave optics was successfully unified with electromagnetic theory by James Clerk Maxwell in the 1860s.The next development in optical theory came in 1899 when Max Planck correctly modelled blackbody radiation by assuming that the exchange of energy between light and matter only occurred in discrete amounts he called quanta. In 1905, Albert Einstein published the theory of the photoelectric effect that firmly established the quantization of light itself. In 1913, Niels Bohr showed that atoms could only emit discrete amounts of energy, thus explaining the discrete lines seen in emission and absorption spectra. The understanding of the interaction between light and matter which followed from these developments not only formed the basis of quantum optics but also was crucial for the development of quantum mechanics as a whole. The ultimate culmination, the theory of quantum electrodynamics, explains all optics and electromagnetic processes in general as the result of the exchange of real and virtual photons.Quantum optics gained practical importance with the inventions of the maser in 1953 and of the laser in 1960. Following the work of Paul Dirac in quantum field theory, George Sudarshan, Roy J. Glauber, and Leonard Mandel applied quantum theory to the electromagnetic field in the 1950s and 1960s to gain a more detailed understanding of photodetection and the statistics of light.

Question: What can be used to separate colors from white light?
Answer: prism
Optics began with the development of lenses by the ancient Egyptians and Mesopotamians. The earliest known lenses, made from polished crystal, often quartz, date from as early as 700 BC for Assyrian lenses such as the Layard/Nimrud lens. The ancient Romans and Greeks filled glass spheres with water to make lenses. These practical developments were followed by the development of theories of light and vision by ancient Greek and Indian philosophers, and the development of geometrical optics in the Greco-Roman world. The word optics comes from the ancient Greek word ὀπτική (optikē), meaning "appearance, look".Greek philosophy on optics broke down into two opposing theories on how vision worked, the "intromission theory" and the "emission theory". The intro-mission approach saw vision as coming from objects casting off copies of themselves (called eidola) that were captured by the eye. With many propagators including Democritus, Epicurus, Aristotle and their followers, this theory seems to have some contact with modern theories of what vision really is, but it remained only speculation lacking any experimental foundation.

Question: Who is responsible of developing the first lenses?
Answer: ancient Egyptians and Mesopotamians
The laws of reflection and refraction can be derived from Fermat's principle which states that the path taken between two points by a ray of light is the path that can be traversed in the least time.

Question: What path does Fermat's principal say takes the shortest time?
Answer: the path taken between two points by a ray of light
Papua New Guinea is richly endowed with natural resources, including mineral and renewable resources, such as forests, marine (including a large portion of the world's major tuna stocks), and in some parts agriculture. The rugged terrain—including high mountain ranges and valleys, swamps and islands—and high cost of developing infrastructure, combined with other factors (including serious law and order problems in some centres and the system of customary land title) makes it difficult for outside developers. Local developers are handicapped by years of deficient investment in education, health, ICT and access to finance. Agriculture, for subsistence and cash crops, provides a livelihood for 85% of the population and continues to provide some 30% of GDP. Mineral deposits, including gold, oil, and copper, account for 72% of export earnings. Oil palm production has grown steadily over recent years (largely from estates and with extensive outgrower output), with palm oil now the main agricultural export. In households participating, coffee remains the major export crop (produced largely in the Highlands provinces), followed by cocoa and coconut oil/copra from the coastal areas, each largely produced by smallholders and tea, produced on estates and rubber. The Iagifu/Hedinia Field was discovered in 1986 in the Papuan fold and thrust belt.Former Prime Minister Sir Mekere Morauta tried to restore integrity to state institutions, stabilise the kina, restore stability to the national budget, privatise public enterprises where appropriate, and ensure ongoing peace on Bougainville following the 1997 agreement which ended Bougainville's secessionist unrest. The Morauta government had considerable success in attracting international support, specifically gaining the backing of the International Monetary Fund (IMF) and the World Bank in securing development assistance loans. Significant challenges face Prime Minister Sir Michael Somare, including gaining further investor confidence, continuing efforts to privatise government assets, and maintaining the support of members of Parliament.

Question: What types of minerals make up New Guinea's exports?
Answer: gold, oil, and copper
Born in Linz, Austria, to Bosnian Croat parents who had moved there from Kotor Varoš in Bosnia and Herzegovina, Kovačić began playing at an early age at the local LASK Linz's academy. In 2007, when Kovačić was 13, he was spotted by scouts from several prominent European clubs, including Ajax, Inter Milan, Juventus and Bayern Munich, but his family opted to move to Zagreb instead, where he joined the academy of Croatian giants Dinamo Zagreb.

Question: How old was Kovacic when he was first noticed by many prominent scouts?
Answer: 13
Kovačić made his Inter Milan debut three days later on 3 February, coming on as a half-time substitute in a Serie A match against Siena. On 14 February, Kovačić made his European debut before the home crowd at San Siro in UEFA Europa League match against CFR Cluj. He provided the winning assist for Rodrigo Palacio, who made it 2–0 for Inter, impressing the crowd with his performance, and was given standing ovations while being substituted off in the 89th minute. He also played full 90 minutes in the 3–0 away win against CFR Cluj as Inter proceeded to the next round of the 2012–13 UEFA Europa League.Kovačić made his first domestic league start for Inter in the next round of Serie A in a 1–4 away loss against Fiorentina. In the round of 16 of the UEFA Europa League, Inter was drawn to play against Tottenham Hotspur. After a 3–0 loss in London, Inter needed a 4–0 win in Milan to proceed to the next round. The match ended in a 4–1 win for Inter after the match went into extra time, with Kovačić playing as a starter. He impressed with his composure and playmaking ability, once again receiving ovations by the fans. Then-Inter manager Andrea Stramaccioni hailed his performances on several occasions, describing him as a "star for the future".On 30 March, Kovačić was a starter in his first Derby d'Italia against Juventus at San Siro. The derby ended in a 1–2 win for Juventus, with Kovačić starting the action that resulted in Rodrigo Palacio's 1–1 equalizer. Kovačić was a starter in Inter's next Serie A match, a 0–2 away win against Sampdoria, as well as in their surprising 3–4 loss to Atalanta at San Siro, where he provided an assist for Ricky Álvarez's goal. By the end of the second half of the season, he was a starter in all of the club's Serie A fixtures, as Inter finished in disappointing ninth place on the Serie A table. In May, he was given the "Gentleman Revelation of the Year" award, awarded by Inter fans.

Question: Who was the manager of Inter then?
Answer: Andrea Stramaccioni
On 31 January 2013, Kovačić agreed to a transfer to Inter Milan. It was revealed the deal was worth €15 million in total, with €11 million paid immediately and €4 million when and if Inter qualifies for the UEFA Champions League. Upon his arrival, Kovačić was given the number 10 shirt, previously worn by Wesley Sneijder.

Question: where did kovacic say he would transfer to?
Answer: Inter Milan
Following Manchester United's first league title in 1908 and the FA Cup a year later, it was decided that Bank Street was too restrictive for Davies' ambition; in February 1909, six weeks before the club's first FA Cup title, Old Trafford was named as the home of Manchester United, following the purchase of land for around £60,000. Architect Archibald Leitch was given a budget of £30,000 for construction; original plans called for seating capacity of 100,000, though budget constraints forced a revision to 77,000. The building was constructed by Messrs Brameld and Smith of Manchester. The stadium's record attendance was registered on 25 March 1939, when an FA Cup semi-final between Wolverhampton Wanderers and Grimsby Town drew 76,962 spectators.Bombing in the Second World War destroyed much of the stadium; the central tunnel in the South Stand was all that remained of that quarter. After the war, the club received compensation from the War Damage Commission in the amount of £22,278. While reconstruction took place, the team played its "home" games at Manchester City's Maine Road ground; Manchester United was charged £5,000 per year, plus a nominal percentage of gate receipts. Later improvements included the addition of roofs, first to the Stretford End and then to the North and East Stands. The roofs were supported by pillars that obstructed many fans' views, and they were eventually replaced with a cantilevered structure. The Stretford End was the last stand to receive a cantilevered roof, completed in time for the 1993–94 season. First used on 25 March 1957 and costing £40,000, four 180-foot (55 m) pylons were erected, each housing 54 individual floodlights. These were dismantled in 1987 and replaced by a lighting system embedded in the roof of each stand, which remains in use today.The Taylor Report's requirement for an all-seater stadium lowered capacity at Old Trafford to around 44,000 by 1993. In 1995, the North Stand was redeveloped into three tiers, restoring capacity to approximately 55,000. At the end of the 1998–99 season, second tiers were added to the East and West Stands, raising capacity to around 67,000, and between July 2005 and May 2006, 8,000 more seats were added via second tiers in the north-west and north-east quadrants. Part of the new seating was used for the first time on 26 March 2006, when an attendance of 69,070 became a new Premier League record. The record was pushed steadily upwards before reaching its peak on 31 March 2007, when 76,098 spectators saw Manchester United beat Blackburn Rovers 4–1, with just 114 seats (0.15 per cent of the total capacity of 76,212) unoccupied. In 2009, reorganisation of the seating resulted in a reduction of capacity by 255 to 75,957. Manchester United has the second highest average attendance of European football clubs only behind Borussia Dortmund.

Question: Where was additional seating added at Old Trafford which allowed for a new Premier League attendance record to be set?
Answer: north-west and north-east quadrants
Following an eighth-place finish in the 1969–70 season and a poor start to the 1970–71 season, Busby was persuaded to temporarily resume managerial duties, and McGuinness returned to his position as reserve team coach. In June 1971, Frank O'Farrell was appointed as manager, but lasted less than 18 months before being replaced by Tommy Docherty in December 1972. Docherty saved Manchester United from relegation that season, only to see them relegated in 1974; by that time the trio of Best, Law, and Charlton had left the club. The team won promotion at the first attempt and reached the FA Cup final in 1976, but were beaten by Southampton. They reached the final again in 1977, beating Liverpool 2–1. Docherty was dismissed shortly afterwards, following the revelation of his affair with the club physiotherapist's wife.Dave Sexton replaced Docherty as manager in the summer of 1977. Despite major signings, including Joe Jordan, Gordon McQueen, Gary Bailey, and Ray Wilkins, the team failed to achieve any significant results; they finished in the top two in 1979–80 and lost to Arsenal in the 1979 FA Cup Final. Sexton was dismissed in 1981, even though the team won the last seven games under his direction. He was replaced by Ron Atkinson, who immediately broke the British record transfer fee to sign Bryan Robson from West Bromwich Albion. Under Atkinson, Manchester United won the FA Cup twice in three years – in 1983 and 1985. In 1985–86, after 13 wins and two draws in its first 15 matches, the club was favourite to win the league, but finished in fourth place. The following season, with the club in danger of relegation by November, Atkinson was dismissed.

Question: When did Manchester United reach the final again?
Answer: 1977
Manchester United has rivalries with Arsenal, Leeds United, Liverpool, and Manchester City, against whom they contest the Manchester derby.The rivalry with Liverpool is rooted in competition between the cities during the Industrial Revolution when Manchester was famous for its textile industry while Liverpool was a major port. The two clubs are the most successful English teams in both domestic and European competitions; and between them they have won 38 league titles, 9 European Cups, 4 UEFA Cups, 4 UEFA Super Cups, 19 FA Cups, 13 League Cups, 1 FIFA Club World Cup, 1 Intercontinental Cup and 36 FA Community Shields. It is considered to be one of the biggest rivalries in the association football world and is considered the most famous fixture in English football.The "Roses Rivalry" with Leeds stems from the Wars of the Roses, fought between the House of Lancaster and the House of York, with Manchester United representing Lancashire and Leeds representing Yorkshire.The rivalry with Arsenal arises from the numerous times the two teams, as well as managers Alex Ferguson and Arsène Wenger, have battled for the Premier League title. With 33 titles between them (20 for Manchester United, 13 for Arsenal) this fixture has become known as one of the finest Premier League match-ups in history.

Question: who are MANU'S rivals?
Answer: Arsenal, Leeds United, Liverpool, and Manchester City
Manchester United is one of the most popular football clubs in the world, with one of the highest average home attendances in Europe. The club states that its worldwide fan base includes more than 200 officially recognised branches of the Manchester United Supporters Club (MUSC), in at least 24 countries. The club takes advantage of this support through its worldwide summer tours. Accountancy firm and sports industry consultants Deloitte estimate that Manchester United has 75 million fans worldwide, while other estimates put this figure closer to 333 million. The club has the third highest social media following in the world among sports teams (after Barcelona and Real Madrid), with over 71 million Facebook fans as of September 2016. A 2014 study showed that Manchester United had the loudest fans in the Premier League.Supporters are represented by two independent bodies; the Independent Manchester United Supporters' Association (IMUSA), which maintains close links to the club through the MUFC Fans Forum, and the Manchester United Supporters' Trust (MUST). After the Glazer family's takeover in 2005, a group of fans formed a splinter club, F.C. United of Manchester. The West Stand of Old Trafford – the "Stretford End" – is the home end and the traditional source of the club's most vocal support.

Question: Which football club has around 75 million fans worldwide according to sports industry consultants?
Answer: Manchester United
Astronomers such as David Morrison argue that the galactic equator is an entirely arbitrary line and can never be precisely drawn, because it is impossible to determine the Milky Way's exact boundaries, which vary depending on clarity of view. Jenkins claimed he drew his conclusions about the location of the galactic equator from observations taken at above 11,000 feet (3,400 m), an altitude that gives a clearer image of the Milky Way than the Maya had access to. Furthermore, since the Sun is half a degree wide, its solstice position takes 36 years to precess its full width. Jenkins himself noted that even given his determined location for the line of the galactic equator, its most precise convergence with the center of the Sun already occurred in 1998, and so asserts that, rather than 2012, the galactic alignment instead focuses on a multi-year period centered in 1998.There is no clear evidence that the classic Maya were aware of precession. Some Maya scholars, such as Barbara MacLeod, Michael Grofe, Eva Hunt, Gordon Brotherston, and Anthony Aveni, have suggested that some Mayan holy dates were timed to precessional cycles, but scholarly opinion on the subject remains divided. There is also little evidence, archaeological or historical, that the Maya placed any importance on solstices or equinoxes. It is possible that only the earliest among Mesoamericans observed solstices, but this is also a disputed issue among Mayanists. There is also no evidence that the classic Maya attached any importance to the Milky Way; there is no glyph in their writing system to represent it, and no astronomical or chronological table tied to it.

Question: What profession is David Morrison?
Answer: Astronomers
Many assertions about the year 2012 form part of Mayanism, a non-codified collection of New Age beliefs about ancient Maya wisdom and spirituality. The term is distinct from "Mayanist," used to refer to an academic scholar of the Maya. Archaeoastronomer Anthony Aveni says that while the idea of "balancing the cosmos" was prominent in ancient Maya literature, the 2012 phenomenon did not draw from those traditions. Instead, it was bound up with American concepts such as the New Age movement, 2012 millenarianism, and the belief in secret knowledge from distant times and places. Themes found in 2012 literature included "suspicion towards mainstream Western culture", the idea of spiritual evolution, and the possibility of leading the world into the New Age by individual example or by a group's joined consciousness. The general intent of this literature was not to warn of impending doom but "to foster counter-cultural sympathies and eventually socio-political and 'spiritual' activism". Aveni, who has studied New Age and search for extraterrestrial intelligence (SETI) communities, describes 2012 narratives as the product of a "disconnected" society: "Unable to find spiritual answers to life's big questions within ourselves, we turn outward to imagined entities that lie far off in space or time—entities that just might be in possession of superior knowledge."

Question: What year was the substance of suspicion towards mainstream Western culture found in literature?
Answer: 2012

Question: When did the phenomenon occur?
Answer: 2012
Very little is known about the god Bʼolon Yokteʼ. According to an article by Mayanists Markus Eberl and Christian Prager in British Anthropological Reports, his name is composed of the elements "nine", ʼOK-teʼ (the meaning of which is unknown), and "god". Confusion in classical period inscriptions suggests that the name was already ancient and unfamiliar to contemporary scribes. He also appears in inscriptions from Palenque, Usumacinta, and La Mar as a god of war, conflict, and the underworld. In one stele he is portrayed with a rope tied around his neck, and in another with an incense bag, together signifying a sacrifice to end a cycle of years.Based on observations of modern Maya rituals, Gronemeyer and MacLeod claim that the stela refers to a celebration in which a person portraying Bolon Yokteʼ Kʼuh was wrapped in ceremonial garments and paraded around the site. They note that the association of Bolon Yokteʼ Kʼuh with bʼakʼtun 13 appears to be so important on this inscription that it supersedes more typical celebrations such as "erection of stelae, scattering of incense" and so forth. Furthermore, they assert that this event was indeed planned for 2012 and not the 7th century. Mayanist scholar Stephen Houston contests this view by arguing that future dates on Maya inscriptions were simply meant to draw parallels with contemporary events, and that the words on the stela describe a contemporary rather than a future scene.

Question: Who wrote about the mysterious god B'olon Yokte?
Answer: Mayanists Markus Eberl and Christian Prager
A melody (from Greek μελῳδία, melōidía, "singing, chanting"), also tune, voice, or line, is a linear succession of musical tones that the listener perceives as a single entity. In its most literal sense, a melody is a combination of pitch and rhythm, while more figuratively, the term can include successions of other musical elements such as tonal color. It may be considered the foreground to the background accompaniment. A line or part need not be a foreground melody.

Question: what is a melody in the most literal sense?
Answer: a combination of pitch and rhythm
Different musical styles use melody in different ways. For example:

Question: Different music uses what differently?
Answer: melody