funded unless you’re looking for a genetic basis. Neither extreme is right, and the data show why. There’s only a 50 percent concordance between genetics and the development of schizophrenia.”

 

 

 

［A］ Many scientists now believe that some experiences can actually alter the structure of the brain.

 

［B］ Meanwhile, genetic claims are being made for a host of ordinary and abnormal behaviors, from addiction to shyness and even to political views and divorce. If who we are is determined from conception, then our efforts to change or to influence our children may be futile. There may also be no basis for insisting that people behave themselves and conform to laws. Thus, the revolution in thinking about genes has monumental consequences for how we view ourselves as human beings.

 

［C］ DNA is not destiny; experience plays a powerful role, too.

 

［D］ A gene is only a probability for a given trait, not a guarantee. For that trait to be expressed, a gene often must be “turned on” by an outside force before it does its job. High levels of stress apparently activate a variety of genes, including those suspected of being involved in fear, shyness and some mental illnesses.

 

［E］ The human body contains about 100,000 genes, of which 50,000 to 70,000 are involved in brain function.

 

［F］ The inextricable interplay between genes and environment is evident in disorders like alcoholism, anorexia, or overeating that are characterized by abnormal behaviors. Scientists spiritedly debate whether such syndromes are more or less biologically driven. If they are mainly biological—rather than psychological, social, and cultural—then there may be a genetic basis for them.

 

［G］ The age-old question of whether nature or nurture determines temperament seems finally to have been decided in favor of Mother Nature and her ever-deepening gene pool.

 

 

 

参考答案：41 C 42 G 43 A 44 E 45 D

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