Answer the following question given this paragraph: Catalytic converters in cars increase the rates of several important reactions. Unburned hydrocarbons can more easily be converted to carbon dioxide and water in the presence of a catalyst. Additionally, carbon monoxide (a harmful gas produced by incomplete combustion of fuel) is further oxidized to carbon dioxide, and nitrous oxide compounds (which contribute to smog and acid rain) are transformed back into nitrogen and oxygen gases. By passing car exhaust over these catalysts before their release into the air, the emissions from a combustion engine are made into much less harmful substances, resulting in a much cleaner atmosphere. Q: Unburned hydrocarbons can more easily be converted to carbon dioxide and water in the presence of a what? Choices: - temperature - methane - Ethanol - catalyst A:
catalyst
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Answer the following question given this paragraph: Unlike energy, matter doesn't need to be constantly added to ecosystems. Instead, matter is recycled through ecosystems. Water and elements such as carbon and nitrogen that living things need are used over and over again. Q: Unlike energy, what doesn't need to be constantly added to ecosystems because it is recycled through ecosystems? Choices: - water - nutrients - vapor - matter A:
matter
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Answer the following question given this paragraph: Photochemical smog consists mainly of ozone (O 3 ). The ozone in smog is the same compound as the ozone in the ozone layer,(O 3 ). But ozone in smog is found near the ground. Figure below shows how it forms. When nitrogen oxides and VOCs are heated by the Sun, they lose oxygen atoms. The oxygen atoms combine with molecules of oxygen to form ozone. Smog ozone is harmful to humans and other living things. Q: What dangerous oxygen compound is found in ground level smog? Choices: - argon - sulfur dioxide - neon - ozone A:
ozone
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Answer the following question given this paragraph: Fatty Acids. Saturated fatty acids have straight chains, like the three fatty acids shown on the left. Unsaturated fatty acids have bent chains, like all the other fatty acids in the figure. Q: What type of fatty acids have bent chains? Choices: - cholesterol - saturated fatty acids - lipids - unsaturated fatty acids A:
unsaturated fatty acids
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