Problem: Infection:

Other microscopic procedures may also aid in identifying infectious agents. Almost all cells readily stain with a number of basic dyes due to the electrostatic attraction between negatively charged cellular molecules and the positive charge on the dye. A cell is normally transparent under a microscope, and using a stain increases the contrast of a cell with its background. Staining a cell with a dye such as Giemsa stain or crystal violet allows a microscopist to describe its size, shape, internal and external components and its associations with other cells. The response of bacteria to different staining procedures is used in the taxonomic classification of microbes as well. Two methods, the Gram stain and the acid-fast stain, are the standard approaches used to classify bacteria and to diagnosis of disease. The Gram stain identifies the bacterial groups Firmicutes and Actinobacteria, both of which contain many significant human pathogens. The acid-fast staining procedure identifies the Actinobacterial genera Mycobacterium and Nocardia.

What is Geimsa stain?
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A: a dye

Problem: Old Persian is the Old Iranian dialect as it was spoken in south-western Iran by the inhabitants of Parsa, who also gave their name to their region and language. Genuine Old Persian is best attested in one of the three languages of the Behistun inscription, composed circa 520 BC, and which is the last inscription (and only inscription of significant length) in which Old Persian is still grammatically correct. Later inscriptions are comparatively brief, and typically simply copies of words and phrases from earlier ones, often with grammatical errors, which suggests that by the 4th century BC the transition from Old Persian to Middle Persian was already far advanced, but efforts were still being made to retain an "old" quality for official proclamations.
During what century was the change from old to middle Persian just beginning?
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Answer: unanswerable

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
Several South Slavic languages are spoken by millions of people in Southern Europe. Serbian is spoken in Serbia, Bosnia, and Croatia; Bulgarian is spoken in Bulgaria; Croatian is spoken in Croatia and Bosnia; Bosnian is spoken in Bosnia; Slovene is spoken in Slovenia; and Macedonian is spoken in Macedonia.
What languages are spoken by millions of people in Northern Europe?
A: unanswerable

Context and question: Antarctica is colder than the Arctic for three reasons. First, much of the continent is more than 3,000 m (9,800 ft) above sea level, and temperature decreases with elevation in the troposphere. Second, the Arctic Ocean covers the north polar zone: the ocean's relative warmth is transferred through the icepack and prevents temperatures in the Arctic regions from reaching the extremes typical of the land surface of Antarctica. Third, the Earth is at aphelion in July (i.e., the Earth is farthest from the Sun in the Antarctic winter), and the Earth is at perihelion in January (i.e., the Earth is closest to the Sun in the Antarctic summer). The orbital distance contributes to a colder Antarctic winter (and a warmer Antarctic summer) but the first two effects have more impact.
How high is the continent of Antarctica above sea level?
Answer: 3,000 m

Question: ^10 Sub-groups of Slovenes include Prekmurians, Hungarian Slovenes, Carinthian Slovenes, Venetian Slovenes, Resians, and the extinct Carantanians and Somogy Slovenes.
Is there an answer to this question: What are the current sub-groups of Slovenes?

Answer: Prekmurians, Hungarian Slovenes, Carinthian Slovenes, Venetian Slovenes, Resians

Problem: Gregorian calendar:

The Gregorian calendar improves the approximation made by the Julian calendar by skipping three Julian leap days in every 400 years, giving an average year of 365.2425 mean solar days long. This approximation has an error of about one day per 3,300 years with respect to the mean tropical year. However, because of the precession of the equinoxes, the error with respect to the vernal equinox (which occurs, on average, 365.24237 days apart near 2000) is 1 day every 7,700 years, assuming a constant time interval between vernal equinoxes, which is not true. By any criterion, the Gregorian calendar is substantially more accurate than the 1 day in 128 years error of the Julian calendar (average year 365.25 days).

What is the approximate error for every 3,300 years?
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A:
one day