Given a question and a context passage, generate the answer having the word or phrase from the context passage. Here, the answer should be a shortest continous span from the passage.
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Question: Context: Telomeres may regulate human disease by at least two independent mechanisms. First, replicative senescence occurs once short telomeres generate DNA-damage signals that produce a barrier to tumor progression. Second, telomere position effects (TPE) could change gene expression at intermediate telomere lengths in cultured human cells. Here we report that telomere length may contribute to the pathogenesis of facioscapulohumeral muscular dystrophy (FSHD). FSHD is a late-onset disease genetically residing only 25-60 kilobases from the end of chromosome 4q. We used a floxable telomerase to generate isogenic clones with different telomere lengths from affected patients and their unaffected siblings. DUX4, the primary candidate for FSHD pathogenesis, is upregulated over ten-fold in FSHD myoblasts and myotubes with short telomeres, and its expression is inversely proportional to telomere length. FSHD may be the first known human disease in which TPE contributes to age-related phenotype. 
 Question: Which disease is associated with the ectopic expression of the protein encoded by the gene DUX4?

Answer: fshd


Question: Context: Cory Hightower (born July 30, 1979) is a professional basketball player who was selected by the San Antonio Spurs in the 2nd round (54th pick) in the 2000 NBA Draft. 
 Question: Player Cory Hightower played for which team?

Answer: san antonio spurs


Question: Context: Countries must learn to share water fairly if they are to prevent warring over water as population growth and climate change make it ever more scarce. Farming uses 70 percent of the fresh water taken from the world's lakes and rivers and need from farms is set to increase by 14 percent in the next 30 years. Water conflicts can happen in water-stressed areas among local communities and between countries. The lack of instruments for water sharing _ already difficult conditions. In the absence of clear rules, things will not be organized or arranged in order and power plays an important role. While humans drink between 2 and 5 litres of water a day, it takes 1,000-2,000 litres to produce a kilogram of wheat and up to 15,000 litres to produce a kilo of grain-fed beef. The daily consumption of water per person is a thousand times more than the consumption through drinking. Already 1.1 billion people lack clean water and, with the world's population set to grow from 6.5 billion to 8 billion by 2025, 1.8 billion people will face water scarcity by then. Global warming will exacerbate the problem, especially in poor, dry areas. To improve cross-border cooperation on water use, the 10 countries on the Nile are negotiating a water-sharing agreement which the Food and Agriculture Organisation hopes will be a model for other areas where the scarce water can be shared out peacefully. 
 Question: What's the passage mainly about?

Answer:
countries must learn to share water fairly.