Problem: Another way to look at differences between populations is to measure genetic differences rather than physical differences between groups. The mid-20th-century anthropologist William C. Boyd defined race as: "A population which differs significantly from other populations in regard to the frequency of one or more of the genes it possesses. It is an arbitrary matter which, and how many, gene loci we choose to consider as a significant 'constellation'". Leonard Lieberman and Rodney Kirk have pointed out that "the paramount weakness of this statement is that if one gene can distinguish races then the number of races is as numerous as the number of human couples reproducing." Moreover, the anthropologist Stephen Molnar has suggested that the discordance of clines inevitably results in a multiplication of races that renders the concept itself useless. The Human Genome Project states "People who have lived in the same geographic region for many generations may have some alleles in common, but no allele will be found in all members of one population and in no members of any other."
How numerous would the number of races be if one gene can distinguish races?
The answer is the following: number of human couples reproducing

Problem: Capacitors may retain a charge long after power is removed from a circuit; this charge can cause dangerous or even potentially fatal shocks or damage connected equipment. For example, even a seemingly innocuous device such as a disposable-camera flash unit, powered by a 1.5 volt AA battery, has a capacitor which may contain over 15 joules of energy and be charged to over 300 volts. This is easily capable of delivering a shock. Service procedures for electronic devices usually include instructions to discharge large or high-voltage capacitors, for instance using a Brinkley stick. Capacitors may also have built-in discharge resistors to dissipate stored energy to a safe level within a few seconds after power is removed. High-voltage capacitors are stored with the terminals shorted, as protection from potentially dangerous voltages due to dielectric absorption or from transient voltages the capacitor may pick up from static charges or passing weather events.
How are the terminals of high voltage capacitors stored?
The answer is the following: with the terminals shorted

Problem: In September 1940, Japan decided to cut China's only land line to the outside world by seizing Indochina, which was controlled at the time by Vichy France. Japanese forces broke their agreement with the Vichy administration and fighting broke out, ending in a Japanese victory. On 27 September Japan signed a military alliance with Germany and Italy, becoming one of the three Axis Powers. In practice, there was little coordination between Japan and Germany until 1944, by which time the U.S. was deciphering their secret diplomatic correspondence.
When did Japan invade Indochina?
The answer is the following: September 1940

Problem: Enisa Kafadar argues that there is only one Serbo-Croatian language with several varieties. This has made possible to include all four varieties into a new grammar book. Daniel Bunčić concludes that it is a pluricentric language, with four standard variants spoken in Serbia, Croatia, Montenegro and Bosnia and Herzegovina. The mutual intelligibility between their speakers "exceeds that between the standard variants of English, French, German, or Spanish". Other linguists have argued that the differences between the variants of Serbo-Croatian are less significant than those between the variants of English, German,, Dutch, and Hindi-Urdu.
Who concluded that Serbo-Croatian is a pluricentric language?
The answer is the following:
Daniel Bunčić