Given a context passage, generate a question from the passage such that its answer is shortest continous span from the passage.
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Question: Greenwich is on the River, five miles from the middle of London, and its history is two thousand years old. The first English people were fishermen there, and they named the place Greenwich, meaning "green village". Later the English kings and queens lived at Greenwich in their beautiful places. The name of the earliest palace was Placentia. Henry VIII lived there. He knew that England must be strong at sea. So he started two big ship-yards at Greenwich. But trouble was coming to Greenwich. In 1649, a war started in England and for eleven years there was no king. The men who had worked for him at Placentia decided to live the place themselves. They sold all its beautiful things. Finally, the war ended and King Charles II came back. But Placentia was falling down. So King Charles built a new and bigger palace, which is now open to the public. At this time, Charles was worried about losing so many of its ships at sea: their sailors did not know how to tell exactly where they were. So in 1675, Charles made John Flamsteed, the first astronomer in England, try to find the answer. Flamsteed worked in a new building on the high ground in Greenwich Park. From it with a telescope which he made himself, Flamsteed could look all round the sky. And he did, night after night, for twenty years. Carrying on Flamsteed's work a hundred years later, an astronomer called Harrison finally made a clock which told the time at sea, and helped sailors to know where they were. You can see Harrison's clock, still working, in Greenwich's museum of the sea. Because of Flamsteed's work, every country in the world now tells its time by Greenwich Time.

Answer: Who made the first clock which could tell the time at sea?


Question: Forces deployed to the first Gulf War report more ill health than veterans who did not serve there. Many studies of post-Gulf morbidity are based on relatively small sample sizes and selection bias is often a concern. In a setting where selection bias relating to the ill health of veterans may be reduced, we: i) examined self-reported adult ill health in a large sample of male UK Gulf War veterans and a demographically similar non-deployed comparison group; and ii) explored self-reported ill health among veterans who believed that they had Gulf War syndrome. This study uses data from a retrospective cohort study of reproduction and child health in which a validated postal questionnaire was sent to all UK Gulf War veterans (GWV) and a comparison cohort of Armed Service personnel who were not deployed to the Gulf (NGWV). The cohort for analysis comprises 42,818 males who responded to the questionnaire. We confirmed that GWV report higher rates of general ill health. GWV were significantly more likely to have reported at least one new medical symptom or disease since 1990 than NGWV (61% versus 37%, OR 2.7, 95% CI 2.5-2.8). They were also more likely to report higher numbers of symptoms. The strongest associations were for mood swings (OR 20.9, 95%CI 16.2-27.0), memory loss/lack of concentration (OR 19.6, 95% CI 15.5-24.8), night sweats (OR 9.9, 95% CI 6.5-15.2), general fatigue (OR 9.6, 95% CI 8.3-11.1) and sexual dysfunction (OR 4.6, 95%CI 3.2-6.6). 6% of GWV believed they had Gulf War syndrome (GWS), and this was associated with the highest symptom reporting. Increased levels of reported ill health among GWV were confirmed. This study was the first to use a questionnaire which did not focus specifically on the veterans' symptoms themselves. Nevertheless, the results are consistent with those of other studies of post-Gulf war illness and thus strengthen overall findings in this area of research. Further examination of the mechanisms underlying the reporting of ill health is required.

Answer: What memory problems are reported in the " Gulf war syndrome"


Question: To investigate the clinical feature of Parkinson's disease (PD) with restless leg syndrome (RLS) and the pathogenesis of RLS. We conducted a cross-sectional and control study. The case group concluded 31 PD with RLS patients, meanwhile 39 PD patients were selected as the control group. Clinical history, clinical manifestations, complications and laboratory examinations were compared respectively between the two groups. All the RLS symptoms did not appear in RLS patients until the PD symptoms came out. Significant differences were found in complications such as swallow disturbance, constipation and illusion, when we compared the two PD groups (P < 0.05). Compared with the PD or healthy group, the level of serum ferritin and the H-reflex latency of tibial nerve were significantly decreased in PD with RLS group (P < 0.05). Secondary RLS is a complication of PD. Deficiency of iron and decreased inhibition function of spinal cord may lead to the occurrence of RLS in PD patients. When their motor symptoms are serious and complications are more common, PD patients are more possible to have RLS symptoms.

Answer:
Which deficiency is the cause of restless leg syndrome?