Problem: National Archives and Records Administration:

Archival descriptions of the permanent holdings of the federal government in the custody of NARA are stored in Archival Research Catalog (ARC). The archival descriptions include information on traditional paper holdings, electronic records, and artifacts. As of December 2012, the catalog consisted of about 10 billion logical data records describing 527,000 artifacts and encompassing 81% of NARA's records. There are also 922,000 digital copies of already digitized materials.

Where are archival descriptions of holdings under the custody of NARA stored?
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A: Archival Research Catalog (ARC)

Problem: Violent incidents occurred throughout the Piedmont of the state as white insurgents struggled to maintain white supremacy in the face of social changes after the war and granting of citizenship to freedmen by federal constitutional amendments. After former Confederates were allowed to vote again, election campaigns from 1872 on were marked by violent intimidation of blacks and Republicans by white Democratic paramilitary groups, known as the Red Shirts. Violent incidents took place in Charleston on King Street in September 6 and in nearby Cainhoy on October 15, both in association with political meetings before the 1876 election. The Cainhoy incident was the only one statewide in which more whites were killed than blacks. The Red Shirts were instrumental in suppressing the black Republican vote in some areas in 1876 and narrowly electing Wade Hampton as governor, and taking back control of the state legislature. Another riot occurred in Charleston the day after the election, when a prominent Republican leader was mistakenly reported killed.
What granted Freeman were American citizenship?
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Answer: federal constitutional amendments.

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
Jared Diamond describes an "Evil Quartet" of habitat destruction, overkill, introduced species, and secondary extinctions. Edward O. Wilson prefers the acronym HIPPO, standing for Habitat destruction, Invasive species, Pollution, human over-Population, and Over-harvesting. The most authoritative classification in use today is IUCN's Classification of Direct Threats which has been adopted by major international conservation organizations such as the US Nature Conservancy, the World Wildlife Fund, Conservation International, and BirdLife International.
What is the most invasive classification in use today?
A: unanswerable

Context and question: In a grounded-emitter transistor circuit, such as the light-switch circuit shown, as the base voltage rises, the emitter and collector currents rise exponentially. The collector voltage drops because of reduced resistance from collector to emitter. If the voltage difference between the collector and emitter were zero (or near zero), the collector current would be limited only by the load resistance (light bulb) and the supply voltage. This is called saturation because current is flowing from collector to emitter freely. When saturated, the switch is said to be on.
What causes reduced resistance from collector to emitter?
Answer: unanswerable

Question: Many of the instruments used to perform medieval music still exist, but in different forms. Medieval instruments included the wood flute (which in the 21st century is made of metal), the recorder and plucked string instruments like the lute. As well, early versions of the organ, fiddle (or vielle), and trombone (called the sackbut) existed. Medieval instruments in Europe had most commonly been used singly, often self accompanied with a drone note, or occasionally in parts. From at least as early as the 13th century through the 15th century there was a division of instruments into haut (loud, shrill, outdoor instruments) and bas (quieter, more intimate instruments).
Is there an answer to this question: What was the medieval flute made from?

Answer: wood

Problem: Richard Feynman:

Feynman was elected a Foreign Member of the Royal Society (ForMemRS) in 1965. At this time in the early 1960s, Feynman exhausted himself by working on multiple major projects at the same time, including a request, while at Caltech, to "spruce up" the teaching of undergraduates. After three years devoted to the task, he produced a series of lectures that eventually became The Feynman Lectures on Physics. He wanted a picture of a drumhead sprinkled with powder to show the modes of vibration at the beginning of the book. Concerned over the connections to drugs and rock and roll that could be made from the image, the publishers changed the cover to plain red, though they included a picture of him playing drums in the foreword. The Feynman Lectures on Physics occupied two physicists, Robert B. Leighton and Matthew Sands, as part-time co-authors for several years. Even though the books were not adopted by most universities as textbooks, they continue to sell well because they provide a deep understanding of physics. Many of his lectures and miscellaneous talks were turned into other books, including The Character of Physical Law, QED: The Strange Theory of Light and Matter, Statistical Mechanics, Lectures on Gravitation, and the Feynman Lectures on Computation.

What was the name of the book Feynman wrote about the dark and nothingness?
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A:
unanswerable