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Victoria's youngest son, Leopold, was affected by the blood-clotting disease haemophilia B and two of her five daughters, Alice and Beatrice, were carriers. Royal haemophiliacs descended from Victoria included her great-grandsons, Tsarevich Alexei of Russia, Alfonso, Prince of Asturias, and Infante Gonzalo of Spain. The presence of the disease in Victoria's descendants, but not in her ancestors, led to modern speculation that her true father was not the Duke of Kent but a haemophiliac. There is no documentary evidence of a haemophiliac in connection with Victoria's mother, and as male carriers always suffer the disease, even if such a man had existed he would have been seriously ill. It is more likely that the mutation arose spontaneously because Victoria's father was over 50 at the time of her conception and haemophilia arises more frequently in the children of older fathers. Spontaneous mutations account for about a third of cases.
How old was Victorias father at the time of her death?
A: unanswerable

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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.
What type of system does London Underground use?
A: four-rail system

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The city is also in the process of implementing a 5-year and 20 year Bike Action Plan with a goal of attaining 14 to 35% bicycle transportation mode share by 2030 through the installation of enhanced bicycle infrastructure throughout the city. Other environmentally focused initiatives include curbside recycling, curbside composting bins (in addition to trash, yard-waste, and recycle bins), farmers' markets, community gardens, garden-share, an urban forest initiative, a hazardous materials home-collection service, green business certification, and a municipal bus system which is currently being revamped to integrate with the soon-to-open Expo Line.
The city has two bike Action Plans of how many years?
A: 5-year and 20

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The official published membership statistics, such as those mentioned above, include only those who submit reports for their personal ministry; official statistics do not include inactive and disfellowshipped individuals or others who might attend their meetings. As a result, only about half of those who self-identified as Jehovah's Witnesses in independent demographic studies are considered active by the faith itself. The 2008 US Pew Forum on Religion & Public Life survey found a low retention rate among members of the religion: about 37% of people raised in the religion continued to identify themselves as Jehovah's Witnesses.
What percentage of people who join the Jehovah's Witnesses as an adult end up being considered as inactive?
A:
unanswerable