Input: Article: The London Underground in England is one of the few networks that uses a four-rail system. The additional rail carries the electrical return that, on third rail and overhead networks, is provided by the running rails. On the London Underground, a top-contact third rail is beside the track, energized at +420v DC, and a top-contact fourth rail is located centrally between the running rails at −210v DC, which combine to provide a traction voltage of 630v DC. London Underground is now upgrading its fourth rail system to 750v DC with a positive conductor rail energised to +500v DC and a negative conductor rail energised to -250v DC. However, many older sections in tunnels are still energised to 630v DC. The same system was used for Milan's earliest underground line, Milan Metro's line 1, whose more recent lines use an overhead catenary or a third rail.

Now answer this question: What is the purpose of the forth rail?

Output: carries the electrical return


Article: Zinc is included in most single tablet over-the-counter daily vitamin and mineral supplements. Preparations include zinc oxide, zinc acetate, and zinc gluconate. It is believed to possess antioxidant properties, which may protect against accelerated aging of the skin and muscles of the body; studies differ as to its effectiveness. Zinc also helps speed up the healing process after an injury. It is also suspected of being beneficial to the body's immune system. Indeed, zinc deficiency may have effects on virtually all parts of the human immune system.

Question: What is the benefit of zinc after injury?
Ans: speed up the healing


Here is a question about this article: In 2010, bills to abolish the death penalty in Kansas and in South Dakota (which had a de facto moratorium at the time) were rejected. Idaho ended its de facto moratorium, during which only one volunteer had been executed, on November 18, 2011 by executing Paul Ezra Rhoades; South Dakota executed Donald Moeller on October 30, 2012, ending a de facto moratorium during which only two volunteers had been executed. Of the 12 prisoners whom Nevada has executed since 1976, 11 waived their rights to appeal. Kentucky and Montana have executed two prisoners against their will (KY: 1997 and 1999, MT: 1995 and 1998) and one volunteer, respectively (KY: 2008, MT: 2006). Colorado (in 1997) and Wyoming (in 1992) have executed only one prisoner, respectively.
What is the answer to this question: Who was executed on October 30, 2012?
****
So... Donald Moeller


The problem: Answer a question about this article:
The decline in the value of the U.S. dollar corresponds to price inflation, which is a rise in the general level of prices of goods and services in an economy over a period of time. A consumer price index (CPI) is a measure estimating the average price of consumer goods and services purchased by households. The United States Consumer Price Index, published by the Bureau of Labor Statistics, is a measure estimating the average price of consumer goods and services in the United States. It reflects inflation as experienced by consumers in their day-to-day living expenses. A graph showing the U.S. CPI relative to 1982–1984 and the annual year-over-year change in CPI is shown at right.
The rise in level of prices in an economy is referred to as what?
****
The answer: price inflation


Problem: Please answer a question about the following article about 2008 Summer Olympics torch relay:
Of the 80 torch-bearers in London, Sir Steve Redgrave, who started the relay, mentioned to the media that he had received e-mailed pleas to boycott the event and could "see why they would like to make an issue" of it. Francesca Martinez and Richard Vaughan refused to carry the torch, while Konnie Huq decided to carry it and also speak out against China. The pro-Tibetan Member of Parliament Norman Baker asked all bearers to reconsider. Amid pressure from both directions, Prime Minister Gordon Brown welcomed the torch outside 10 Downing Street without holding or touching it. The London relay saw the torch surrounded by what the BBC described as "a mobile protective ring." Protests began as soon as Redgrave started the event, leading to at least thirty-five arrests. In Ladbroke Grove a demonstrator attempted to snatch the torch from Konnie Huq in a momentary struggle, and in a separate incident, a fire extinguisher was set off near the torch. The Chinese ambassador carried the torch through Chinatown after an unpublicized change to the route amid security concerns. The torch made an unscheduled move onto a bus along Fleet Street amid security concerns and efforts to evade the protesters. In an effort to counter the pro-Tibet protesters and show their support for the 2008 Beijing Olympics, more than 2,000 Chinese also gathered on the torch route and demonstrated with signs, banners and Chinese flags. A large number of supporters were concentrated in Trafalgar Square, displaying the Olympic slogan "One World, One Dream".
How many torchbearers took part in the London route?
A: 80


Question: Read this and answer the question

The original post-punk movement ended as the bands associated with the movement turned away from its aesthetics, often in favor of more commercial sounds. Many of these groups would continue recording as part of the new pop movement, with entryism becoming a popular concept. In the United States, driven by MTV and modern rock radio stations, a number of post-punk acts had an influence on or became part of the Second British Invasion of "New Music" there. Some shifted to a more commercial new wave sound (such as Gang of Four), while others were fixtures on American college radio and became early examples of alternative rock. Perhaps the most successful band to emerge from post-punk was U2, who combined elements of religious imagery together with political commentary into their often anthemic music.

What was a driving force behind the revival of the second British Invasion of New Music to America?
Answer:
MTV and modern rock radio stations