Problem: United States Air Force:

Defensive Counterair (DCA) is defined as "all the defensive measures designed to detect, identify, intercept, and destroy or negate enemy forces attempting to penetrate or attack through friendly airspace" (JP 1-02). A major goal of DCA operations, in concert with OCA operations, is to provide an area from which forces can operate, secure from air and missile threats. The DCA mission comprises both active and passive defense measures. Active defense is "the employment of limited offensive action and counterattacks to deny a contested area or position to the enemy" (JP 1-02). It includes both ballistic missile defense and air breathing threat defense, and encompasses point defense, area defense, and high value airborne asset defense. Passive defense is "measures taken to reduce the probability of and to minimize the effects of damage caused by hostile action without the intention of taking the initiative" (JP 1-02). It includes detection and warning; chemical, biological, radiological, and nuclear defense; camouflage, concealment, and deception; hardening; reconstitution; dispersion; redundancy; and mobility, counter-measures, and stealth.

What does the abbreviation DCA stand for? 
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A: Defensive Counterair


Problem: Dwight D. Eisenhower:

In July 1953, an armistice took effect with Korea divided along approximately the same boundary as in 1950. The armistice and boundary remain in effect today, with American soldiers stationed there to guarantee it. The armistice, concluded despite opposition from Secretary Dulles, South Korean President Syngman Rhee, and also within Eisenhower's party, has been described by biographer Ambrose as the greatest achievement of the administration. Eisenhower had the insight to realize that unlimited war in the nuclear age was unthinkable, and limited war unwinnable.

What American official notably opposed the armistice?
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A: Secretary Dulles


Problem: Time:

The most precise timekeeping device of the ancient world was the water clock, or clepsydra, one of which was found in the tomb of Egyptian pharaoh Amenhotep I (1525–1504 BC). They could be used to measure the hours even at night, but required manual upkeep to replenish the flow of water. The Ancient Greeks and the people from Chaldea (southeastern Mesopotamia) regularly maintained timekeeping records as an essential part of their astronomical observations. Arab inventors and engineers in particular made improvements on the use of water clocks up to the Middle Ages. In the 11th century, Chinese inventors and engineers invented the first mechanical clocks driven by an escapement mechanism.

Which inventors made significant improvements on the water clock up until the Middle Ages?
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A: Arab inventors


Problem: Ministry of Defence (United Kingdom):

In April 2008, a £90m contract was signed with Boeing for a "quick fix" solution, so they can fly by 2010: QinetiQ will downgrade the Chinooks—stripping out some of their more advanced equipment.

When was a contract signed for more advanced equipment?
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A:
unanswerable