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The chemical composition of wood varies from species to species, but is approximately 50% carbon, 42% oxygen, 6% hydrogen, 1% nitrogen, and 1% other elements (mainly calcium, potassium, sodium, magnesium, iron, and manganese) by weight. Wood also contains sulfur, chlorine, silicon, phosphorus, and other elements in small quantity.
Which element in wood composes about 42% of its weight?
A: oxygen

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As the 1990s dawned, gamers predicted that competition from technologically superior systems such as the 16-bit Sega Mega Drive/Genesis would mean the immediate end of the NES’s dominance. Instead, during the first year of Nintendo's successor console the Super Famicom (named Super Nintendo Entertainment System outside Japan), the Famicom remained the second highest-selling video game console in Japan, outselling the newer and more powerful NEC PC Engine and Sega Mega Drive by a wide margin. The console remained popular in Japan and North America until late 1993, when the demand for new NES software abruptly plummeted. The final Famicom game released in Japan is Takahashi Meijin no Bōken Jima IV (Adventure Island IV), while in North America, Wario's Woods is the final licensed game. In the wake of ever decreasing sales and the lack of new software titles, Nintendo of America officially discontinued the NES by 1995. However, Nintendo kept producing new Famicom units in Japan until September 25, 2003, and continued to repair Famicom consoles until October 31, 2007, attributing the discontinuation of support to insufficient supplies of parts.
Which example of a system started to mark the end of the SNES dominance?
A: unanswerable

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This period is generally taken to coincide with a major shift in population from southern Mesopotamia toward the north. Ecologically, the agricultural productivity of the Sumerian lands was being compromised as a result of rising salinity. Soil salinity in this region had been long recognized as a major problem. Poorly drained irrigated soils, in an arid climate with high levels of evaporation, led to the buildup of dissolved salts in the soil, eventually reducing agricultural yields severely. During the Akkadian and Ur III phases, there was a shift from the cultivation of wheat to the more salt-tolerant barley, but this was insufficient, and during the period from 2100 BC to 1700 BC, it is estimated that the population in this area declined by nearly three fifths. This greatly upset the balance of power within the region, weakening the areas where Sumerian was spoken, and comparatively strengthening those where Akkadian was the major language. Henceforth Sumerian would remain only a literary and liturgical language, similar to the position occupied by Latin in medieval Europe.
Poorly drained irrigated soils in an arid climate with a good deal of evaporation is responsible for leaving what?
A: dissolved salts

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Several solid dielectrics are available, including paper, plastic, glass, mica and ceramic materials. Paper was used extensively in older devices and offers relatively high voltage performance. However, it is susceptible to water absorption, and has been largely replaced by plastic film capacitors. Plastics offer better stability and ageing performance, which makes them useful in timer circuits, although they may be limited to low operating temperatures and frequencies. Ceramic capacitors are generally small, cheap and useful for high frequency applications, although their capacitance varies strongly with voltage and they age poorly. They are broadly categorized as class 1 dielectrics, which have predictable variation of capacitance with temperature or class 2 dielectrics, which can operate at higher voltage. Glass and mica capacitors are extremely reliable, stable and tolerant to high temperatures and voltages, but are too expensive for most mainstream applications. Electrolytic capacitors and supercapacitors are used to store small and larger amounts of energy, respectively, ceramic capacitors are often used in resonators, and parasitic capacitance occurs in circuits wherever the simple conductor-insulator-conductor structure is formed unintentionally by the configuration of the circuit layout.
What sort of circuit are plastic capacitors especially useful for?
A:
timer circuits