Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
Infrared tracking, also known as infrared homing, refers to a passive missile guidance system, which uses the emission from a target of electromagnetic radiation in the infrared part of the spectrum to track it. Missiles that use infrared seeking are often referred to as "heat-seekers", since infrared (IR) is just below the visible spectrum of light in frequency and is radiated strongly by hot bodies. Many objects such as people, vehicle engines, and aircraft generate and retain heat, and as such, are especially visible in the infrared wavelengths of light compared to objects in the background.
What is another term for heat seekers?
A: unanswerable

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In May 2008, the National Archives announced a five-year agreement to digitize selected records including the complete U.S. Federal Census Collection, 17901930, passenger lists from 18201960 and WWI and WWII draft registration cards. The partnership agreement allows for exclusive use of the digitized records by Ancestry.com for a 5-year embargo period at which point the digital records will be turned over to the National Archives.
What happens after the 5 year embargo that allows Ancestry.com exclusive use of digitized records?
A: turned over to the National Archives

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Research commissioned by Cecil King from Mark Abrams of Sussex University, The Newspaper Reading Public of Tomorrow, identified demographic changes which suggested reasons why the Herald might be in decline. The new paper was intended to add a readership of 'social radicals' to the Herald's 'political radicals'. Launched with an advertising budget of 400,000 the brash new paper "burst forth with tremendous energy", according to The Times. Its initial print run of 3.5 million was attributed to 'curiosity' and the 'advantage of novelty', and had declined to the previous circulation of the Daily Herald (1.2 million) within a few weeks.
What was named as a potential reason for the Herald's decline?
A: demographic changes

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"Race" is still sometimes used within forensic anthropology (when analyzing skeletal remains), biomedical research, and race-based medicine. Brace has criticized this, the practice of forensic anthropologists for using the controversial concept "race" out of convention when they in fact should be talking about regional ancestry. He argues that while forensic anthropologists can determine that a skeletal remain comes from a person with ancestors in a specific region of Africa, categorizing that skeletal as being "black" is a socially constructed category that is only meaningful in the particular context of the United States, and which is not itself scientifically valid.
What term would Brace prefer forensic anthropologists use?
A:
regional ancestry