Problem: Sahara:

The Byzantine Empire ruled the northern shores of the Sahara from the 5th to the 7th centuries. After the Muslim conquest of Arabia (Arabian peninsula) the Muslim conquest of North Africa began in the mid-7th to early 8th centuries, Islamic influence expanded rapidly on the Sahara. By the end of 641 all of Egypt was in Muslim hands. The trade across the desert intensified. A significant slave trade crossed the desert. It has been estimated that from the 10th to 19th centuries some 6,000 to 7,000 slaves were transported north each year.

What group of people ruled the northern shoes of the Sahara?
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A: Byzantine Empire

Problem: The U.S. Census Bureau reported that in 2000, 24.0% of San Diego residents were under 18, and 10.5% were 65 and over. As of 2011[update] the median age was 35.6; more than a quarter of residents were under age 20 and 11% were over age 65. Millennials (ages 18 through 34) constitute 27.1% of San Diego's population, the second-highest percentage in a major U.S. city. The San Diego County regional planning agency, SANDAG, provides tables and graphs breaking down the city population into 5-year age groups.
What regional planning agency offers graphs and tables of census information for San Diego?
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Answer: SANDAG

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
The city shares a 15-mile (24 km) border with Mexico that includes two border crossings. San Diego hosts the busiest international border crossing in the world, in the San Ysidro neighborhood at the San Ysidro Port of Entry. A second, primarily commercial border crossing operates in the Otay Mesa area; it is the largest commercial crossing on the California-Baja California border and handles the third-highest volume of trucks and dollar value of trade among all United States-Mexico land crossings.
Where is the farthest commercial crossing at the border?
A: unanswerable

Context and question: The Carboniferous was a time of active mountain building, as the supercontinent Pangea came together. The southern continents remained tied together in the supercontinent Gondwana, which collided with North America-Europe (Laurussia) along the present line of eastern North America. This continental collision resulted in the Hercynian orogeny in Europe, and the Alleghenian orogeny in North America; it also extended the newly uplifted Appalachians southwestward as the Ouachita Mountains. In the same time frame, much of present eastern Eurasian plate welded itself to Europe along the line of the Ural mountains. There were two major oceans in the Carboniferous the Panthalassa and Paleo-Tethys. Other minor oceans were shrinking and eventually closed the Rheic Ocean (closed by the assembly of South and North America), the small, shallow Ural Ocean (which was closed by the collision of Baltica, and Siberia continents, creating the Ural Mountains) and Proto-Tethys Ocean.
What was the effect of Laurussia impacting Gondwana in North America?
Answer: the Alleghenian orogeny

Question: It was only in the 1980s that digital telephony transmission networks became possible, such as with ISDN networks, assuring a minimum bit rate (usually 128 kilobits/s) for compressed video and audio transmission. During this time, there was also research into other forms of digital video and audio communication. Many of these technologies, such as the Media space, are not as widely used today as videoconferencing but were still an important area of research. The first dedicated systems started to appear in the market as ISDN networks were expanding throughout the world. One of the first commercial videoconferencing systems sold to companies came from PictureTel Corp., which had an Initial Public Offering in November, 1984.
Is there an answer to this question: What other minimum bit rate is not as widely used as videoconferencing?

Answer: unanswerable

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
St. John's was the starting point for the first non-stop transatlantic aircraft flight, by Alcock and Brown in a modified Vickers Vimy IV bomber, in June 1919, departing from Lester's Field in St. John's and ending in a bog near Clifden, Connemara, Ireland. In July 2005, the flight was duplicated by American aviator and adventurer Steve Fossett in a replica Vickers Vimy aircraft, with St. John's International Airport substituting for Lester's Field (now an urban and residential part of the city).
What aircraft did Steve Fossett use for his flight in July 2005?
A:
replica Vickers Vimy