Problem: Antenna (radio):

The net quality of a ground reflection depends on the topography of the surface. When the irregularities of the surface are much smaller than the wavelength, we are in the regime of specular reflection, and the receiver sees both the real antenna and an image of the antenna under the ground due to reflection. But if the ground has irregularities not small compared to the wavelength, reflections will not be coherent but shifted by random phases. With shorter wavelengths (higher frequencies), this is generally the case.

What frequencies is associated with shorter wavelengths?
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A: higher frequencies


Problem: In March 2015, the winds and storm surge created by Cyclone Pam resulted in waves of 3 metres (9.8 ft) to 5 metres (16 ft) breaking over the reef of the outer islands caused damage to houses, crops and infrastructure. On Nui the sources of fresh water were destroyed or contaminated. The flooding in Nui and Nukufetau caused many families to shelter in evacuation centres or with other families. Nui suffered the most damage of the three central islands (Nui, Nukufetau and Vaitupu); with both Nui and Nukufetau suffering the loss of 90% of the crops. Of the three northern islands (Nanumanga, Niutao, Nanumea), Nanumanga suffered the most damage, with 60-100 houses flooded, with the waves also causing damage to the health facility. Vasafua islet, part of the Funafuti Conservation Area, was severely damaged by Cyclone Pam. The coconut palms were washed away, leaving the islet as a sand bar.
The loss of what caused the Vasafua islet to become  a sand bar due to Cyclone Pam?
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Answer: coconut palms


Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
From April–July, Soviet and German officials made statements regarding the potential for the beginning of political negotiations, while no actual negotiations took place during that time period. The ensuing discussion of a potential political deal between Germany and the Soviet Union had to be channeled into the framework of economic negotiations between the two countries, because close military and diplomatic connections, as was the case before the mid-1930s, had afterward been largely severed. In May, Stalin replaced his Foreign Minister Maxim Litvinov, who was regarded as pro-western and who was also Jewish, with Vyacheslav Molotov, allowing the Soviet Union more latitude in discussions with more parties, not only with Britain and France.
Which Soviet Foreign Minister lost his job because of his unfavorable attitude towards the west?
A: unanswerable


Context and question: The first video game based on the AFL was Arena Football for the C-64 released in 1988. On May 18, 2000, Kurt Warner's Arena Football Unleashed was released by Midway Games for the PlayStation game console. On February 7, 2006 EA Sports released Arena Football for the PlayStation 2 and Xbox. EA Sports released another AFL video game, titled Arena Football: Road to Glory, on February 21, 2007, for the PlayStation 2.
For what system was the first Arena Football League video game released?
Answer: the C-64


Question: At birth, Victoria was fifth in the line of succession after her father and his three older brothers: the Prince Regent, the Duke of York, and the Duke of Clarence (later William IV). The Prince Regent and the Duke of York were estranged from their wives, who were both past child-bearing age, so the two eldest brothers were unlikely to have any further children. The Dukes of Kent and Clarence married on the same day 12 months before Victoria's birth, but both of Clarence's daughters (born in 1819 and 1820 respectively) died as infants. Victoria's grandfather and father died in 1820, within a week of each other, and the Duke of York died in 1827. On the death of her uncle George IV in 1830, Victoria became heiress presumptive to her next surviving uncle, William IV. The Regency Act 1830 made special provision for the Duchess of Kent to act as regent in case William died while Victoria was still a minor. King William distrusted the Duchess's capacity to be regent, and in 1836 declared in her presence that he wanted to live until Victoria's 18th birthday, so that a regency could be avoided.
Is there an answer to this question: What was the length of time between the deaths of Victoria's father and brother?

Answer: unanswerable


Problem: Database:


XML databases are a type of structured document-oriented database that allows querying based on XML document attributes. XML databases are mostly used in enterprise database management, where XML is being used as the machine-to-machine data interoperability standard. XML database management systems include commercial software MarkLogic and Oracle Berkeley DB XML, and a free use software Clusterpoint Distributed XML/JSON Database. All are enterprise software database platforms and support industry standard ACID-compliant transaction processing with strong database consistency characteristics and high level of database security.

Where are XML databases never used?
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A:
unanswerable