Problem: Uranium:

In 1972, the French physicist Francis Perrin discovered fifteen ancient and no longer active natural nuclear fission reactors in three separate ore deposits at the Oklo mine in Gabon, West Africa, collectively known as the Oklo Fossil Reactors. The ore deposit is 1.7 billion years old; then, uranium-235 constituted about 3% of the total uranium on Earth. This is high enough to permit a sustained nuclear fission chain reaction to occur, provided other supporting conditions exist. The capacity of the surrounding sediment to contain the nuclear waste products has been cited by the U.S. federal government as supporting evidence for the feasibility to store spent nuclear fuel at the Yucca Mountain nuclear waste repository.

How old are the ore deposits in the Oklo mine?
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A: 1.7 billion years


Problem: A cappella:

Increased interest in modern a cappella (particularly collegiate a cappella) can be seen in the growth of awards such as the Contemporary A Cappella Recording Awards (overseen by the Contemporary A Cappella Society) and competitions such as the International Championship of Collegiate A Cappella for college groups and the Harmony Sweepstakes for all groups. In December 2009, a new television competition series called The Sing-Off aired on NBC. The show featured eight a cappella groups from the United States and Puerto Rico vying for the prize of $100,000 and a recording contract with Epic Records/Sony Music. The show was judged by Ben Folds, Shawn Stockman, and Nicole Scherzinger and was won by an all-male group from Puerto Rico called Nota. The show returned for a second and third season, won by Committed and Pentatonix, respectively.

What popular a capella competition is not specific to college groups?
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A: Harmony Sweepstakes


Problem: Norfolk Island:

As of 2004[update], 2532 telephone main lines are in use, a mix of analog (2500) and digital (32) circuits. Satellite communications services are planned.[citation needed] There is one locally based radio station (Radio Norfolk 89.9FM), broadcasting on both AM and FM frequencies. There is also one TV station, Norfolk TV, featuring local programming, plus transmitters for Australian channels ABC, SBS, Imparja Television and Southern Cross Television. The Internet country code top-level domain (ccTLD) is .nf.

How many analog telephone lines were being removed on Norfolk Island as of 2004?
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A: unanswerable


Problem: Karl Popper:

In 2004, philosopher and psychologist Michel ter Hark (Groningen, The Netherlands) published a book, called Popper, Otto Selz and the rise of evolutionary epistemology, in which he claimed that Popper took some of his ideas from his tutor, the German psychologist Otto Selz. Selz never published his ideas, partly because of the rise of Nazism, which forced him to quit his work in 1933, and the prohibition of referring to Selz' work. Popper, the historian of ideas and his scholarship, is criticised in some academic quarters for his rejection of Plato, Hegel and Marx.

When did Selz start his work?
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A:
unanswerable