Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
Evidence of wheeled vehicles appeared in the mid 4th millennium BC, near-simultaneously in Mesopotamia, the Northern Caucasus (Maykop culture) and Central Europe. The wheel initially took the form of the potter's wheel. The new concept quickly led to wheeled vehicles and mill wheels. The Sumerians' cuneiform writing system is the oldest (or second oldest after the Egyptian hieroglyphs) which has been deciphered (the status of even older inscriptions such as the Jiahu symbols and Tartaria tablets is controversial). The Sumerians were among the first astronomers, mapping the stars into sets of constellations, many of which survived in the zodiac and were also recognized by the ancient Greeks. They were also aware of the five planets that are easily visible to the naked eye.
When did evidence of wheeled vehicles appear throughout the world?
A: mid 4th millennium BC

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While asthma is a well recognized condition, there is not one universal agreed upon definition. It is defined by the Global Initiative for Asthma as "a chronic inflammatory disorder of the airways in which many cells and cellular elements play a role. The chronic inflammation is associated with airway hyper-responsiveness that leads to recurrent episodes of wheezing, breathlessness, chest tightness and coughing particularly at night or in the early morning. These episodes are usually associated with widespread but variable airflow obstruction within the lung that is often reversible either spontaneously or with treatment".
What does hyper-responsiveness of the airways cause?
A: episodes of wheezing, breathlessness, chest tightness and coughing

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Gay and lesbian people can have sexual relationships with someone of the opposite sex for a variety of reasons, including the desire for a perceived traditional family and concerns of discrimination and religious ostracism. While some LGBT people hide their respective orientations from their spouses, others develop positive gay and lesbian identities while maintaining successful heterosexual marriages. Coming out of the closet to oneself, a spouse of the opposite sex, and children can present challenges that are not faced by gay and lesbian people who are not married to people of the opposite sex or do not have children.
What is one reason that a homosexual would engage in heterosexual behavior?
A: religious ostracism

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Though still predominantly green, post-2004 series incorporate other colors to better distinguish different denominations. As a result of a 2008 decision in an accessibility lawsuit filed by the American Council of the Blind, the Bureau of Engraving and Printing is planning to implement a raised tactile feature in the next redesign of each note, except the $1 and the version of the $100 bill already in process. It also plans larger, higher-contrast numerals, more color differences, and distribution of currency readers to assist the visually impaired during the transition period.
Which organization filed a numeral lawsuit?
A:
unanswerable