QUES: Bacteria can be grown in the laboratory on nutrient culture media, but viruses need living cells in which to replicate. Many vaccines to infectious diseases can be grown in fertilised chicken eggs. Millions of eggs are used each year to generate the annual flu vaccine requirements, a complex process that takes about six months after the decision is made as to what strains of virus to include in the new vaccine. A problem with using eggs for this purpose is that people with egg allergies are unable to be immunised, but this disadvantage may be overcome as new techniques for cell-based rather than egg-based culture become available. Cell-based culture will also be useful in a pandemic when it may be difficult to acquire a sufficiently large quantity of suitable sterile, fertile eggs.

Why is there no difficulty faced in using poultry to cultivate vaccines?
What is the answer?
ANS: unanswerable
QUES: Multi-layer printed circuit boards have trace layers inside the board. This is achieved by laminating a stack of materials in a press by applying pressure and heat for a period of time. This results in an inseparable one piece product. For example, a four-layer PCB can be fabricated by starting from a two-sided copper-clad laminate, etch the circuitry on both sides, then laminate to the top and bottom pre-preg and copper foil. It is then drilled, plated, and etched again to get traces on top and bottom layers.

What kind of circuit boards result from applying pressure and cold air for a period of time?
What is the answer?
ANS: unanswerable
QUES: In the early hours of 7 December (Hawaiian time), Japan launched a major surprise carrier-based air strike on Pearl Harbor without explicit warning, which crippled the U.S. Pacific Fleet, leaving eight American battleships out of action, 188 American aircraft destroyed, and 2,403 American citizens dead. At the time of the attack, the U.S. was not officially at war anywhere in the world, which means that the people killed or property destroyed at Pearl Harbor by the Japanese attack had a non-combatant status.[nb 11] The Japanese had gambled that the United States, when faced with such a sudden and massive blow, would agree to a negotiated settlement and allow Japan free rein in Asia. This gamble did not pay off. American losses were less serious than initially thought: The American aircraft carriers, which would prove to be more important than battleships, were at sea, and vital naval infrastructure (fuel oil tanks, shipyard facilities, and a power station), submarine base, and signals intelligence units were unscathed. Japan's fallback strategy, relying on a war of attrition to make the U.S. come to terms, was beyond the IJN's capabilities.

How many Americans died in the Pearl Harbor attacks?
What is the answer?
ANS:
2,403