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Chemistry
226)'Carbon dioxide cycle' implies that
	the carbon dioxide structure is cyclic		ocygen is changed into carbon dioxide by respiration of human beings and then to oxygen and carbon dioxide by green plants
	the carbon dioxide consumes oxygen		carbon dioxide moves in the air in a cycle
Answer :
227)Soda bicarbonate is useful as a fire extinguisher because
	it decomposes on heating to give carbon dioxide, which extinguishes fires		it releases water which extinguishes fires
	it serves as a blanket for fires		it emits a foam which extinguishes fires
Answer :
228)It is dangerous to have coal or charcoal burning in a closed room because
	burning consumes all the oxygen and breathing becomes difficult		the amount of heat produces is intolerable
	there is serious risk of fire		it produces the poisonous gas carbon monoxide
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229)The pair of bases in natural nucleic acids which are held by hydrogen bonds is
	guanine and thymine		guanine and cytosine
	adenine and thymine		uracil and thymine
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230)Though the temperature inside lighted electric bulb is arounf 27000C, the filament does not burn because
	it does not burn in closed system		it is made of non-metallic substance
	the oxygen necessary for combustion (and burning) is not available as the bulb is evacuated and filled with pure nitrogen of inert gas		the metal of which it is made is resistant to burning
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231)Steel contains
	5 - 10% carbon		20% carbom
	no carbon		0.1 - 2% carbon
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232)Saliva hydrolyses strach to
	glucose		fructose
	sucrose		carbon dioxide and water
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233)In the process of respiration, the component of air used is
	oxygen		nitrogen
	carbon dioxide		inert gases
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234)Allugel tablets used to reduce acidity contain
	sodium carbonate		sodium hydroxide
	aluminium hydroxide		magnesium hydroxide
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235)The main use of salt in the diet is to
	make the taste of food better		produce in small amount the hydrochloric acid required for the digestion of food
	increase the solubility of food particles in water		ease the process of cooking
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236)The metal most abundantly used by man is
	copper		gold
	iron		aluminium
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237)A balanced fertiliser for plants is
	compost		urea
	super phosphate		super phosphate of lime
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238)A codon
	may have more than one meaning depending upon its location in the mRNA polymer		helps position in the new amino acids correctly by hydrogen bonding with an anticodon of tRNA
	signals that three particular amino acids be incorporated into a growing peptide		is a sequence of four bases in a row
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239)The human body contains the maximum amount of
	proteins		fats
	plasma		water
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240)Anaemic patients are deficient in
	calcium		iodine
	iron		magnesium
Answer :

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