Question 12 is based on the passage you have just heard.

        (12) [Public interest was aroused by the latest discovery of a changed gene in obese mice. ]The news was made known by Rockefeller University geneticist Jeffrey Friedman. The researchers believe this gene influences development of a hormone that tells organism how fat or full it is. (13) [Those with the changed gene may not sense when they have eaten enough or if they have sufficient fatty tissue, and thus can’t tell when to stop eating. ]

        The researchers also reported finding a gene nearly identical to the mouse obesity gene in humans. The operation of this gene in humans has not yet been demonstrated, however. (14) [Still, professionals like University of Vermont psychologist Esther Rothblum reacted enthusiastically, “This research indicates that people really are born with a tendency to have a certain weight, just as they are to have a particular skin color or height.” ]

        Actually, behavioral geneticists believe that less than half of the total weight variation is programmed in the genes, while height is almost entirely genetically determined. Whatever role genes play, Americans are getting fatter. A survey by the Center for Disease Control found that obesity has increased greatly over the last 10 years. (15)[ Such rapid change underlines the role of environmental factors like the abundance of rich foods in Americans’ overeating. ]The Center for Disease Control has also found that teens are far less physically active than they were even a decade ago.

        Accepting that weight is predetermined can relieve guilt for overweight people. But people’s belief that they cannot control their weight can itself contribute to obesity.

12. What does the speaker say has aroused public interest?（讲话者说是什么引起了公众的兴趣？） 

解析：A。录音开头即提到，最近在肥胖老鼠体内发现的一种变异基因引起了公众的兴趣，A项中的a changed gene in obese mice属于原词复现，而recent finding是录音中the latest discovery的同义替换，故A为正确答案。

错项排除：录音中没有提及gene modification，故B项排除。录音中只是通过对老鼠的实验引出肥胖与基因的关系，用来解释可能造成肥胖的因素，并没有提及新发现的减肥方法，C项只是利用录音中的latest discovery及weight进行细节拼凑，故排除。录音开头围绕obese mice的话题展开论述，但没有提到self-repairing ability（自我修复力），故排除D项。