The problem: Answer a question about this article:
The third largest city in Spain and the 24th most populous municipality in the European Union, Valencia has a population of 809,267 within its administrative limits on a land area of 134.6 km2 (52 sq mi). The urban area of Valencia extending beyond the administrative city limits has a population of between 1,561,000 and 1,564,145. 1,705,742 or 2,300,000 or 2,516,818 people live in the Valencia metropolitan area. Between 2007 and 2008 there was a 14% increase in the foreign born population with the largest numeric increases by country being from Bolivia, Romania and Italy.
How many inhabitants live within Valencia's limits?
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The answer: 809,267

The problem: Answer a question about this article:
The mantle is equivalent to 10 to 15 Earth masses and is rich in water, ammonia and methane. As is customary in planetary science, this mixture is referred to as icy even though it is a hot, dense fluid. This fluid, which has a high electrical conductivity, is sometimes called a waterammonia ocean. The mantle may consist of a layer of ionic water in which the water molecules break down into a soup of hydrogen and oxygen ions, and deeper down superionic water in which the oxygen crystallises but the hydrogen ions float around freely within the oxygen lattice. At a depth of 7000 km, the conditions may be such that methane decomposes into diamond crystals that rain downwards like hailstones. Very-high-pressure experiments at the Lawrence Livermore National Laboratory suggest that the base of the mantle may comprise an ocean of liquid carbon with floating solid 'diamonds'.
What does the fluid in Neptune have a high conductivity of?
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The answer: electrical

The problem: Answer a question about this article:
Russia feared losing Russian America without compensation in some future conflict, especially to the British. While Alaska attracted little interest at the time, the population of nearby British Columbia started to increase rapidly a few years after hostilities ended. Therefore, the Russian emperor, Alexander II, decided to sell Alaska. In 1859 the Russians offered to sell the territory to the United States, hoping that its presence in the region would offset the plans of Russia's greatest regional rival, the United Kingdom.
Who did the Russians offer to sell Alaska to?
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The answer: the United States

The problem: Answer a question about this article:
There are a number of proposals to redefine certain of the SI base units in terms of fundamental physical constants. This has already been done for the metre, which is defined in terms of a fixed value of the speed of light. The most urgent unit on the list for redefinition is the kilogram, whose value has been fixed for all science (since 1889) by the mass of a small cylinder of platinumiridium alloy kept in a vault just outside Paris. While nobody knows if the mass of the International Prototype Kilogram has changed since 1889 the value 1 kg of its mass expressed in kilograms is by definition unchanged and therein lies one of the problems it is known that over such a timescale the many similar PtIr alloy cylinders kept in national laboratories around the world, have changed their relative mass by several tens of parts per million, however carefully they are stored, and the more so the more they have been taken out and used as mass standards. A change of several tens of micrograms in one kilogram is equivalent to the current uncertainty in the value of the Planck constant in SI units.
What measurement is deemed most important to redefine in terms of physical constants?
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The answer:
the kilogram