单项选择题

Different Phases of Death
Modern scientists divide the process of dying into two phases—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 (复活). Biological death occurs when changes in the organism lead to the "breaking up" of vital cells and tissues. Death is then unchangeable and final.
Scientists have been seeking a way to prolong the period of clinical death so that the organism can remain alive before biological death occurs. The best method developed so far involves cooling of the organism, combined with narcotic (麻醉的) sleep. By slowing down the body" s metabolism (新陈代谢), 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 scientist 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 an artery (动脉). The monkey"s blood pressure decreased and an hour later both the heart and respiration 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 an artery in the direction of the heart and started artificial respiration. After two minutes Keta"s heart became active once more. After fifteen minutes, spontaneous (自然产生的) respiration 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 (注射器) and ran with it around the room. Her behavior differed little from that of a healthy animal. What happened to the monkey when she was restored to the original state again