Article: In 1901, 10-inch disc records were introduced, followed in 1903 by 12-inch records. These could play for more than three and four minutes respectively, while contemporary cylinders could only play for about two minutes. In an attempt to head off the disc advantage, Edison introduced the Amberol cylinder in 1909, with a maximum playing time of 4½ minutes (at 160 rpm), which in turn were superseded by Blue Amberol Records, which had a playing surface made of celluloid, a plastic, which was far less fragile. Despite these improvements, during the 1910s discs decisively won this early format war, although Edison continued to produce new Blue Amberol cylinders for an ever-dwindling customer base until late in 1929. By 1919 the basic patents for the manufacture of lateral-cut disc records had expired, opening the field for countless companies to produce them. Analog disc records would dominate the home entertainment market until they were outsold by the digital compact disc in the late 1980s (which was in turn supplanted by digital audio recordings distributed via online music stores and Internet file sharing).

Question: What disc format was the least fragile prior to 1919?
Ans: Amberol cylinder


Article: The army is led by a civilian Secretary of the Army, who has the statutory authority to conduct all the affairs of the army under the authority, direction and control of the Secretary of Defense. The Chief of Staff of the Army, who is the highest-ranked military officer in the army, serves as the principal military adviser and executive agent for the Secretary of the Army, i.e., its service chief; and as a member of the Joint Chiefs of Staff, a body composed of the service chiefs from each of the four military services belonging to the Department of Defense who advise the President of the United States, the Secretary of Defense, and the National Security Council on operational military matters, under the guidance of the Chairman and Vice Chairman of the Joint Chiefs of Staff. In 1986, the Goldwater–Nichols Act mandated that operational control of the services follows a chain of command from the President to the Secretary of Defense directly to the unified combatant commanders, who have control of all armed forces units in their geographic or function area of responsibility. Thus, the secretaries of the military departments (and their respective service chiefs underneath them) only have the responsibility to organize, train and equip their service components. The army provides trained forces to the combatant commanders for use as directed by the Secretary of Defense.

Question: Who is the highest-ranked military officer in the army?
Ans: The Chief of Staff


Article: Tibet (i/tᵻˈbɛt/; Wylie: Bod, pronounced [pʰø̀ʔ]; Chinese: 西藏; pinyin: Xīzàng) is a region on the Tibetan Plateau in Asia. It is the traditional homeland of the Tibetan people as well as some other ethnic groups such as Monpa, Qiang and Lhoba peoples and is now also inhabited by considerable numbers of Han Chinese and Hui people. Tibet is the highest region on Earth, with an average elevation of 4,900 metres (16,000 ft). The highest elevation in Tibet is Mount Everest, earth's highest mountain rising 8,848 m (29,029 ft) above sea level.

Question: How many feet above sea level does earth's highest mountain rise?
Ans: 29,029


Article: The D-Day Normandy landings on June 6, 1944, were costly but successful. A month later, the invasion of Southern France took place, and control of forces in the southern invasion passed from the AFHQ to the SHAEF. Many prematurely considered that victory in Europe would come by summer's end—however the Germans did not capitulate for almost a year. From then until the end of the war in Europe on May 8, 1945, Eisenhower, through SHAEF, commanded all Allied forces, and through his command of ETOUSA had administrative command of all U.S. forces on the Western Front north of the Alps. He was ever mindful of the inevitable loss of life and suffering that would be experienced on an individual level by the troops under his command and their families. This prompted him to make a point of visiting every division involved in the invasion. Eisenhower's sense of responsibility was underscored by his draft of a statement to be issued if the invasion failed. It has been called one of the great speeches of history:

Question: When did the Normandy invasion occur?
Ans:
June 6, 1944