The poorer mental function seen among alcoholics, many of whom also regularly smoke cigarettes, may be partly caused by the long-term effects of nicotine , new study suggests.  "People who are also smokers are more dangerous," Dr. Jennifer M. Glass, of the University of Michigan's Addiction Research Center, said. In her study, "cigarette smoking had bad effects on IQ and thinking," she said. This finding may seem wrong because many smokers feel better after smoking.  Studies show that up to 87 percent of alcoholics smoke cigarettes. Yet, few studies have looked into cigarette smoking as a reason that might explain the cognitive deficits  reported among alcoholics.  To find out that connection, Glass and her partners examined brain function among 172 men from the same community, including 103 men who  are alcoholics. The team found that heavy smokers and those alcoholics both had lower IQ scores.  In the further study, the experts found that smoking also appeared to be connected with weaker verbal   and visual-spatial reasoning  . So, though smoking did not account for all of the poorer mental function among the alcoholics, it did seem to account for some of the effects, the report shows. The passage mainly tells us that_.
smoking and drinking may make IQ and thinking ability poor. how smoking and drinking influence IQ and thinking ability. people should give up smoking and drinking immediately. why some people have weaker verbal and visual-spatial reasoning.
Question: The poorer mental function seen among alcoholics, many of whom also regularly smoke cigarettes, may be partly caused by the long-term effects of nicotine , new study suggests.  "People who are also smokers are more dangerous," Dr. Jennifer M. Glass, of the University of Michigan's Addiction Research Center, said. In her study, "cigarette smoking had bad effects on IQ and thinking," she said. This finding may seem wrong because many smokers feel better after smoking.  Studies show that up to 87 percent of alcoholics smoke cigarettes. Yet, few studies have looked into cigarette smoking as a reason that might explain the cognitive deficits  reported among alcoholics.  To find out that connection, Glass and her partners examined brain function among 172 men from the same community, including 103 men who  are alcoholics. The team found that heavy smokers and those alcoholics both had lower IQ scores.  In the further study, the experts found that smoking also appeared to be connected with weaker verbal   and visual-spatial reasoning  . So, though smoking did not account for all of the poorer mental function among the alcoholics, it did seem to account for some of the effects, the report shows. The passage mainly tells us that_.
A. smoking and drinking may make IQ and thinking ability poor.
B. how smoking and drinking influence IQ and thinking ability.
C. people should give up smoking and drinking immediately.
D. why some people have weaker verbal and visual-spatial reasoning.
Answer: