Problem: Hard rock:

The term "retro-metal" has been applied to such bands as Texas based The Sword, California's High on Fire, Sweden's Witchcraft and Australia's Wolfmother. Wolfmother's self-titled 2005 debut album combined elements of the sounds of Deep Purple and Led Zeppelin. Fellow Australians Airbourne's début album Runnin' Wild (2007) followed in the hard riffing tradition of AC/DC. England's The Darkness' Permission to Land (2003), described as an "eerily realistic simulation of '80s metal and '70s glam", topped the UK charts, going quintuple platinum. The follow-up, One Way Ticket to Hell... and Back (2005), reached number 11, before the band broke up in 2006. Los Angeles band Steel Panther managed to gain a following by sending up 80s glam metal. A more serious attempt to revive glam metal was made by bands of the sleaze metal movement in Sweden, including Vains of Jenna, Hardcore Superstar and Crashdïet.

What country was a serious attempt to revive punk rock attempted?
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A: unanswerable


Problem: Idealist notions took a strong hold among physicists of the early 20th century confronted with the paradoxes of quantum physics and the theory of relativity. In The Grammar of Science, Preface to the 2nd Edition, 1900, Karl Pearson wrote, "There are many signs that a sound idealism is surely replacing, as a basis for natural philosophy, the crude materialism of the older physicists." This book influenced Einstein's regard for the importance of the observer in scientific measurements[citation needed]. In § 5 of that book, Pearson asserted that "...science is in reality a classification and analysis of the contents of the mind...." Also, "...the field of science is much more consciousness than an external world."
When did idealism fall out of practice?
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Answer: unanswerable


Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
For much of Eton's history, junior boys had to act as "fags", or servants, to older boys. Their duties included cleaning, cooking, and running errands. A Library member was entitled to yell at any time and without notice, "Boy, Up!" or "Boy, Queue!", and all first-year boys had to come running. The last boy to arrive was given the task. These practices, known as fagging, were partially phased out of most houses in the 1970s. Captains of House and Games still sometimes give tasks to first-year boys, such as collecting the mail from School Office.[citation needed]
What would junior boys yell at older students?
A: unanswerable


Context and question: Another landmark is the old centre and the canal structure in the inner city. The Oudegracht is a curved canal, partly following the ancient main branch of the Rhine. It is lined with the unique wharf-basement structures that create a two-level street along the canals. The inner city has largely retained its Medieval structure, and the moat ringing the old town is largely intact. Because of the role of Utrecht as a fortified city, construction outside the medieval centre and its city walls was restricted until the 19th century. Surrounding the medieval core there is a ring of late 19th- and early 20th-century neighbourhoods, with newer neighbourhoods positioned farther out. The eastern part of Utrecht remains fairly open. The Dutch Water Line, moved east of the city in the early 19th century required open lines of fire, thus prohibiting all permanent constructions until the middle of the 20th century on the east side of the city.
What is a landmark in the city 
Answer: the old centre and the canal structure in the inner city


Question: Meanwhile, on 10 October 1950, the 89th Tank Battalion was attached to the 1st Cavalry Division, increasing the armor available for the Northern Offensive. On 15 October, after moderate KPA resistance, the 7th Cavalry Regiment and Charlie Company, 70th Tank Battalion captured Namchonjam city. On 17 October, they flanked rightwards, away from the principal road (to Pyongyang), to capture Hwangju. Two days later, the 1st Cavalry Division captured Pyongyang, the North's capital city, on 19 October 1950. Kim Il Sung and his government temporarily moved its capital to Sinuiju – although as UNC forces approached, the government again moved – this time to Kanggye.
Is there an answer to this question: What caused the North Koreans to move their capital for the second time?

Answer: UNC forces approached


Problem: Bird migration:

The migration of birds also aids the movement of other species, including those of ectoparasites such as ticks and lice, which in turn may carry micro-organisms including those of concern to human health. Due to the global spread of avian influenza, bird migration has been studied as a possible mechanism of disease transmission, but it has been found not to present a special risk; import of pet and domestic birds is a greater threat. Some viruses that are maintained in birds without lethal effects, such as the West Nile Virus may however be spread by migrating birds. Birds may also have a role in the dispersal of propagules of plants and plankton.

What has been studied as a mechanism of disease transmission?
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A:
bird migration