Problem: Hazards to aircraft include debris, nesting birds, and reduced friction levels due to environmental conditions such as ice, snow, or rain. Part of runway maintenance is airfield rubber removal which helps maintain friction levels. The fields must be kept clear of debris using cleaning equipment so that loose material does not become a projectile and enter an engine duct (see foreign object damage). In adverse weather conditions, ice and snow clearing equipment can be used to improve traction on the landing strip. For waiting aircraft, equipment is used to spray special deicing fluids on the wings.
For what kind of aircraft is deicing fluid sprayed on the airfield?
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Answer: unanswerable

Problem: In 1963, the teenage Brian May and his father custom-built his signature guitar Red Special, which was purposely designed to feedback. Sonic experimentation figured heavily in Queen's songs. A distinctive characteristic of Queen's music are the vocal harmonies which are usually composed of the voices of May, Mercury, and Taylor best heard on the studio albums A Night at the Opera and A Day at the Races. Some of the ground work for the development of this sound can be attributed to their former producer Roy Thomas Baker, and their engineer Mike Stone. Besides vocal harmonies, Queen were also known for multi-tracking voices to imitate the sound of a large choir through overdubs. For instance, according to Brian May, there are over 180 vocal overdubs in "Bohemian Rhapsody". The band's vocal structures have been compared with the Beach Boys, but May stated they were not "much of an influence".
How many vocal overdubs are in Queen's Bohemian Rhapsody?
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Answer: over 180

Problem: Another view, advanced by Richard Dawkins, is that the existence of God is an empirical question, on the grounds that "a universe with a god would be a completely different kind of universe from one without, and it would be a scientific difference." Carl Sagan argued that the doctrine of a Creator of the Universe was difficult to prove or disprove and that the only conceivable scientific discovery that could disprove the existence of a Creator would be the discovery that the universe is infinitely old.
What did Richard Dawkins believe was difficult to prove?
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Answer:
unanswerable