Problem: Predation:

Mobbing can be an interspecies activity: it is common for birds to respond to mobbing calls of a different species. Many birds will show up at the sight of mobbing and watch and call, but not participate. It should also be noted that some species can be on both ends of a mobbing attack. Crows are frequently mobbed by smaller songbirds as they prey on eggs and young from these birds' nests, but these same crows will cooperate with smaller birds to drive away hawks or larger mammalian predators. On occasion, birds will mob animals that pose no threat.

What is an activity usually done by mammalian predators?
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A: unanswerable


Problem: Throughout the history of the South Slavs, the vernacular, literary, and written languages (e.g. Chakavian, Kajkavian, Shtokavian) of the various regions and ethnicities developed and diverged independently. Prior to the 19th century, they were collectively called "Illyric", "Slavic", "Slavonian", "Bosnian", "Dalmatian", "Serbian" or "Croatian". As such, the term Serbo-Croatian was first used by Jacob Grimm in 1824, popularized by the Vienna philologist Jernej Kopitar in the following decades, and accepted by Croatian Zagreb grammarians in 1854 and 1859. At that time, Serb and Croat lands were still part of the Ottoman and Austrian Empires. Officially, the language was called variously Serbo-Croat, Croato-Serbian, Serbian and Croatian, Croatian and Serbian, Serbian or Croatian, Croatian or Serbian. Unofficially, Serbs and Croats typically called the language "Serbian" or "Croatian", respectively, without implying a distinction between the two, and again in independent Bosnia and Herzegovina, "Bosnian", "Croatian", and "Serbian" were considered to be three names of a single official language. Croatian linguist Dalibor Brozović advocated the term Serbo-Croatian as late as 1988, claiming that in an analogy with Indo-European, Serbo-Croatian does not only name the two components of the same language, but simply charts the limits of the region in which it is spoken and includes everything between the limits (‘Bosnian’ and ‘Montenegrin’). Today, use of the term "Serbo-Croatian" is controversial due to the prejudice that nation and language must match. It is still used for lack of a succinct alternative, though alternative names have been used, such as Bosnian/Croatian/Serbian (BCS), which is often seen in political contexts such as the Hague War Crimes tribunal.
Who first used the term Serbo-Croatian in 1824?
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Answer: Jacob Grimm


Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
The Premier League is the most-watched football league in the world, broadcast in 212 territories to 643 million homes and a potential TV audience of 4.7 billion people. In the 2014–15 season, the average Premier League match attendance exceeded 36,000, second highest of any professional football league behind the Bundesliga's 43,500. Most stadium occupancies are near capacity. The Premier League rank second in the UEFA coefficients of leagues based on performances in European competitions over the past five seasons.
Which league has the highest average attendance in professional football?
A: Bundesliga


Context and question: Philadelphia is also a major hub for Greyhound Lines, which operates 24-hour service to points east of the Mississippi River. Most of Greyhound's services in Philadelphia operate to/from the Philadelphia Greyhound Terminal, located at 1001 Filbert Street in Center City Philadelphia. In 2006, the Philadelphia Greyhound Terminal was the second busiest Greyhound terminal in the United States, after the Port Authority Bus Terminal in New York. Besides Greyhound, six other bus operators provide service to the Center City Greyhound terminal: Bieber Tourways, Capitol Trailways, Martz Trailways, Peter Pan Bus Lines, Susquehanna Trailways, and the bus division for New Jersey Transit. Other services include Megabus and Bolt Bus.
What bus line uses the city as a hub?
Answer: Greyhound Lines


Question: The extraordinary demands of the Punic Wars, in addition to a shortage of manpower, exposed the tactical weaknesses of the manipular legion, at least in the short term. In 217 BC, near the beginning of the Second Punic War, Rome was forced to effectively ignore its long-standing principle that its soldiers must be both citizens and property owners. During the 2nd century BC, Roman territory saw an overall decline in population, partially due to the huge losses incurred during various wars. This was accompanied by severe social stresses and the greater collapse of the middle classes. As a result, the Roman state was forced to arm its soldiers at the expense of the state, which it had not had to do in the past.
Is there an answer to this question: What were soldiers expected to own prior to the year 217 BC?

Answer: property


Problem: High-definition television:

Since 1972, International Telecommunication Union's radio telecommunications sector (ITU-R) had been working on creating a global recommendation for Analog HDTV. These recommendations, however, did not fit in the broadcasting bands which could reach home users. The standardization of MPEG-1 in 1993 also led to the acceptance of recommendations ITU-R BT.709. In anticipation of these standards the Digital Video Broadcasting (DVB) organisation was formed, an alliance of broadcasters, consumer electronics manufacturers and regulatory bodies. The DVB develops and agrees upon specifications which are formally standardised by ETSI.

What is the DVB?
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A:
an alliance of broadcasters, consumer electronics manufacturers and regulatory bodies