Problem: Brain:

Almost all animals are capable of modifying their behavior as a result of experienceeven the most primitive types of worms. Because behavior is driven by brain activity, changes in behavior must somehow correspond to changes inside the brain. Theorists dating back to Santiago Ramon y Cajal argued that the most plausible explanation is that learning and memory are expressed as changes in the synaptic connections between neurons. Until 1970, however, experimental evidence to support the synaptic plasticity hypothesis was lacking. In 1971 Tim Bliss and Terje Lmo published a paper on a phenomenon now called long-term potentiation: the paper showed clear evidence of activity-induced synaptic changes that lasted for at least several days. Since then technical advances have made these sorts of experiments much easier to carry out, and thousands of studies have been made that have clarified the mechanism of synaptic change, and uncovered other types of activity-driven synaptic change in a variety of brain areas, including the cerebral cortex, hippocampus, basal ganglia, and cerebellum. Brain-derived neurotrophic factor (BDNF) and physical activity appear to play a beneficial role in the process.

BDNF is an abbreviation for what term?
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A: Brain-derived neurotrophic factor

Problem: Paper:

Paper is a thin material produced by pressing together moist fibres of cellulose pulp derived from wood, rags or grasses, and drying them into flexible sheets. It is a versatile material with many uses, including writing, printing, packaging, cleaning, and a number of industrial and construction processes.

What is an uncommon use for paper?
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A: unanswerable

Problem: Renewable energy commercialization:

Hydropower is produced in 150 countries, with the Asia-Pacific region generating 32 percent of global hydropower in 2010. China is the largest hydroelectricity producer, with 721 terawatt-hours of production in 2010, representing around 17 percent of domestic electricity use. There are now three hydroelectricity plants larger than 10 GW: the Three Gorges Dam in China, Itaipu Dam across the Brazil/Paraguay border, and Guri Dam in Venezuela. The cost of hydroelectricity is low, making it a competitive source of renewable electricity. The average cost of electricity from a hydro plant larger than 10 megawatts is 3 to 5 U.S. cents per kilowatt-hour.

Hydropower is produced in how many countries?
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A: 150

Problem: Namibia:

Life expectancy at birth is estimated to be 52.2 years in 2012 among the lowest in the world. The AIDS epidemic is a large problem in Namibia. Though its rate of infection is substantially lower than that of its eastern neighbour, Botswana, approximately 13.1% of the adult population is[update] infected with HIV. In 2001, there were an estimated 210,000 people living with HIV/AIDS, and the estimated death toll in 2003 was 16,000. According to the 2011 UNAIDS Report, the epidemic in Namibia "appears to be leveling off." As the HIV/AIDS epidemic has reduced the working-aged population, the number of orphans has increased. It falls to the government to provide education, food, shelter and clothing for these orphans.

How many orphans are there in Namibia?
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A:
unanswerable