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Mark Twain once observed that giving up smoking is easy. He knew, because he’d done it hundreds of times himself, Giving up for ever is a trifle more difficult, apparently, and it is well known that it is much more difficult for some people than for others. Why is this so
Few doctors believe any longer that it is simply a question of will power. And for those people that continue to view addicts as merely "weak", recent genetic research may force a rethink. A study conducted by Jacqueline Vink, of the Free University of Amsterdam, used a database called the Netherlands Twin Register to analyse the smoking habits of twins. Her results suggest that an individual’s degree of nicotine dependence, and even the number of cigarettes he smokes per day, are strongly genetically influenced.
The Netherlands Twin Register is a voluntary database that is prized by geneticists because they allow the comparison of identical twins (who
A. The fraternal twins are much more valued by researchers.
B. Two kinds of twins are often been compared in research.
C. Identical twins are more likely to be addicted to smoking.
D. Fraternal twins are more genetically similar than identical twins.
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