QUES: After the Dambusters raid in 1943 an entirely new system was developed that was required to knock down any low-flying aircraft with a single hit. The first attempt to produce such a system used a 50 mm gun, but this proved inaccurate and a new 55 mm gun replaced it. The system used a centralised control system including both search and targeting radar, which calculated the aim point for the guns after considering windage and ballistics, and then sent electrical commands to the guns, which used hydraulics to point themselves at high speeds. Operators simply fed the guns and selected the targets. This system, modern even by today's standards, was in late development when the war ended.
What did the new system designed after the Dambusters raid supposed to do?

ANS: knock down any low-flying aircraft with a single hit

QUES: The breakup of the Carolingian Empire was accompanied by invasions, migrations, and raids by external foes. The Atlantic and northern shores were harassed by the Vikings, who also raided the British Isles and settled there as well as in Iceland. In 911, the Viking chieftain Rollo (d. c. 931) received permission from the Frankish King Charles the Simple (r. 898922) to settle in what became Normandy.[Q] The eastern parts of the Frankish kingdoms, especially Germany and Italy, were under continual Magyar assault until the invader's defeat at the Battle of Lechfeld in 955. The breakup of the Abbasid dynasty meant that the Islamic world fragmented into smaller political states, some of which began expanding into Italy and Sicily, as well as over the Pyrenees into the southern parts of the Frankish kingdoms.
Who was king of the Franks in 899?

ANS: Charles the Simple

QUES: In 1899, the university opened a national design contest for the new campus. The renowned Philadelphia firm Cope & Stewardson won unanimously with its plan for a row of Collegiate Gothic quadrangles inspired by Oxford and Cambridge Universities. The cornerstone of the first building, Busch Hall, was laid on October 20, 1900. The construction of Brookings Hall, Ridgley, and Cupples began shortly thereafter. The school delayed occupying these buildings until 1905 to accommodate the 1904 World's Fair and Olympics. The delay allowed the university to construct ten buildings instead of the seven originally planned. This original cluster of buildings set a precedent for the development of the Danforth Campus; Cope & Stewardson's original plan and its choice of building materials have, with few exceptions, guided the construction and expansion of the Danforth Campus to the present day.
On what date did Brookings Hall have its cornerstone laid?

ANS: unanswerable

QUES: Fimbriae (sometimes called "attachment pili") are fine filaments of protein, usually 210 nanometres in diameter and up to several micrometers in length. They are distributed over the surface of the cell, and resemble fine hairs when seen under the electron microscope. Fimbriae are believed to be involved in attachment to solid surfaces or to other cells, and are essential for the virulence of some bacterial pathogens. Pili (sing. pilus) are cellular appendages, slightly larger than fimbriae, that can transfer genetic material between bacterial cells in a process called conjugation where they are called conjugation pili or "sex pili" (see bacterial genetics, below). They can also generate movement where they are called type IV pili (see movement, below).
What are pili?

ANS:
cellular appendages