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  3. Modern scientists divide the process of

Modern scientists divide the process of

Loveyou2019-12-17  50
问题 Modern scientists divide the process of dying into two stages--clinical or temporary death and biological death. Clinical death occurs when the vital organs, such as the heart or lungs, have ceased to function, but have not suffered permanent damage. The organism can still be revived. Biological death occurs when changes in the organism lead to the disintegration of vital cells and tissues. Death is then irreversible and final. Scientists have been seeking a way to prolong the period of clinical death so that the organism can be revived before biological death occurs. The best method developed so far involves cooling of the organism, combined with narcotic sleep. By slowing down the body's metabolism, cooling delays the processes leading to biological death. To illustrate how this works, scientists performed an experiment on a six-year-old female monkey called Keta. The scientists put Keta to sleep with a narcotic. Then they surrounded her body with ice-bags and began checking her body temperature. When it had dropped to 28 degrees the scientists began draining blood from its body. The monkey's blood pressure decreased and an hour later both the heart and breathing stopped; clinical death set in. For twenty minutes Keta remained in this state. Her temperature dropped to 22 degrees. At this point the scientists pumped blood into its body in the direction of the heart and started artificial breathing. After two minutes the monkey's heart became active once more. After fifteen minutes, spontaneous breathing began, and after four hours Keta opened her eyes and lifted her head. After six hours, when the scientists tried to give her a penicillin injection, Keta seized the syringe and ran with it around the room. Her behavior differed little from that of a healthy animal. One possible benefit of the experiment discussed in the passage is _______
选项 A.less crowded citiesB.victory over deathC.protection against fatal injuryD.fewer deaths from heart attacks
答案D
解析在该实验中，科学家使母猴麻醉入睡，在它身旁放满冰袋。当它体温达到28度时开始抽血．母猴血压下降．6时后心跳和呼吸停止，进入临床死亡状态。20分钟后它体温降到22度，科学家向心脏的方向给它输血并进行人工呼吸。过了2分钟，母猴心脏开始跳动；又过了15分钟，呼吸启动；4小时后睁眼抬头：6小时后科学家给它注射青霉素，它就开始活蹦乱跳了。这个实验表明，冷冻法延长临床死亡的好处之一就是可以减少心脏病突发引起的死亡。
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