题干

关于现代生物进化理论的叙述,错误的是(  )

A: 基因的自发突变率虽然很低,但对进化非常重要

B:不同基因型的个体对环境的适应性可相同,也可不同

C:环境发生变化时,种群的基因频率可能改变,也可能不变

D:同一群落中的种群相互影响,因此进化的基本单位是群落

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答案(点此获取答案解析)

D

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       When it comes to medical care, many patients and doctors believe “more is better.” But what they do not realize is that overtreatment—too many scans, too many blood tests, too many procedures—may bring harm. Sometimes a test leads you down a path to more and more testing, some of which may be invasive, or to treatment for things that should be left alone.

       Terrence Power, for example, complained that after his wife learned she had Wegener's disease, an uncommon disorder of the immune system, they found it difficult to refuse testing recommended by her doctor. The doctor insisted on office visits every three weeks, even when she was feeling well. He frequently ordered blood tests and X-rays, and repeatedly referred her to specialists for even minor complaints. Even when tests came back negative, more were ordered, and she was hospitalized as prevention when she developed a cold.   She had as many as 25 doctor visits during one six-month period. The couple was spending about $30,000 a year for her care.

       After several years of physical suffering and near financial ruin from the medical costs, the couple began questioning the treatment after discussing with other patients in online support groups. “It's a really hard thing to determine when they've crossed the line,” Mr. Power said. “You think she's getting the best care in the world, but after a while you start to wonder: What is the purpose?” Mr. Power then spoke with his own primary care doctor, who advised him to find a new specialist to oversee Mrs. Power's care. Under the new doctor's care, the regular testing stopped and Mrs. Power's condition stabilized. Now she sees the doctor only four or five times a year.