Problem: Umayyad Caliphate:

The Umayyad Caliphate (Arabic: , trans. Al-Khilafat al-umawiyya) was the second of the four major Islamic caliphates established after the death of Muhammad. This caliphate was centered on the Umayyad dynasty (Arabic: , al-Umawiyyun, or , Banu Umayya, "Sons of Umayya"), hailing from Mecca. The Umayyad family had first come to power under the third caliph, Uthman ibn Affan (r. 644656), but the Umayyad regime was founded by Muawiya ibn Abi Sufyan, long-time governor of Syria, after the end of the First Muslim Civil War in 661 CE/41 AH. Syria remained the Umayyads' main power base thereafter, and Damascus was their capital. The Umayyads continued the Muslim conquests, incorporating the Caucasus, Transoxiana, Sindh, the Maghreb and the Iberian Peninsula (Al-Andalus) into the Muslim world. At its greatest extent, the Umayyad Caliphate covered 15 million km2 (5.79 million square miles), making it the largest empire (in terms of area - not in terms of population) the world had yet seen, and the fifth largest ever to exist.

How many major Islamic caliphates existed after Muhammad's death?
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A: four

Problem: In September 1939, Britain entered the Second World War, which lasted until 1945. During the war, many of London's children were evacuated to avoid the frequent aerial bombing. The suggestion by senior politician Lord Hailsham that the two princesses should be evacuated to Canada was rejected by Elizabeth's mother, who declared, "The children won't go without me. I won't leave without the King. And the King will never leave." Princesses Elizabeth and Margaret stayed at Balmoral Castle, Scotland, until Christmas 1939, when they moved to Sandringham House, Norfolk. From February to May 1940, they lived at Royal Lodge, Windsor, until moving to Windsor Castle, where they lived for most of the next five years. At Windsor, the princesses staged pantomimes at Christmas in aid of the Queen's Wool Fund, which bought yarn to knit into military garments. In 1940, the 14-year-old Elizabeth made her first radio broadcast during the BBC's Children's Hour, addressing other children who had been evacuated from the cities. She stated: "We are trying to do all we can to help our gallant sailors, soldiers and airmen, and we are trying, too, to bear our share of the danger and sadness of war. We know, every one of us, that in the end all will be well."
When did Britain enter WWII?
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Answer: September 1939

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
Oda Nobunaga made innovations in the fields of organization and war tactics, heavily used arquebuses, developed commerce and industry and treasured innovation. Consecutive victories enabled him to realize the termination of the Ashikaga Bakufu and the disarmament of the military powers of the Buddhist monks, which had inflamed futile struggles among the populace for centuries. Attacking from the "sanctuary" of Buddhist temples, they were constant headaches to any warlord and even the Emperor who tried to control their actions. He died in 1582 when one of his generals, Akechi Mitsuhide, turned upon him with his army.
Who used arquebuses a lot?
A: Oda Nobunaga

Context and question: Patterns such as those seen in human physical and genetic variation as described above, have led to the consequence that the number and geographic location of any described races is highly dependent on the importance attributed to, and quantity of, the traits considered. Scientists discovered a skin-lighting mutation that partially accounts for the appearance of Light skin in humans (people who migrated out of Africa northward into what is now Europe) which they estimate occurred 20,000 to 50,000 years ago. The East Asians owe their relatively light skin to different mutations. On the other hand, the greater the number of traits (or alleles) considered, the more subdivisions of humanity are detected, since traits and gene frequencies do not always correspond to the same geographical location. Or as Ossorio & Duster (2005) put it:
What is the consequence of the number and geographic location ascribed to a race highly dependent on?
Answer: the importance attributed to, and quantity of, the traits considered.

Question: Feynman was a keen popularizer of physics through both books and lectures, including a 1959 talk on top-down nanotechnology called There's Plenty of Room at the Bottom, and the three-volume publication of his undergraduate lectures, The Feynman Lectures on Physics. Feynman also became known through his semi-autobiographical books Surely You're Joking, Mr. Feynman! and What Do You Care What Other People Think? and books written about him, such as Tuva or Bust! and Genius: The Life and Science of Richard Feynman by James Gleick.
Is there an answer to this question: What was the name of one of his fiction books?

Answer: unanswerable

Question: The majority of video compression algorithms use lossy compression. Uncompressed video requires a very high data rate. Although lossless video compression codecs perform at a compression factor of 5-12, a typical MPEG-4 lossy compression video has a compression factor between 20 and 200. As in all lossy compression, there is a trade-off between video quality, cost of processing the compression and decompression, and system requirements. Highly compressed video may present visible or distracting artifacts.
Is there an answer to this question: What all mostly use lossy compression?

Answer:
video compression algorithms