题干

如图为自然环境中生物种群数量变化曲线,下列有关叙述错误的是(    )

A:d处波动可能是因为出生率和死亡率变动所致

B:“涸泽而渔”会使鱼的数量下降至b以下,使生态系统发展停滞甚至崩溃

C:灭鼠时如果仅杀死一定数量的老鼠,可能效果适得其反

D:要开发利用动植物资源,最好要等到c点

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D

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    A great invention by an 18-year-old high school student grew out of a simple problem most teenagers meet with.

    “I'm a teenager and I have a cellphone and my cellphone battery always dies,so I was really looking for a way to improve energy storage,” Eesha Khare said on Tuesday. “That's how I came across the super capacitor.”

    The teenager who came from California, and graduated from high school last week,won a $50,000 prize on May 17,2013 at the Intel International Science and Engineering Fair for creating a device that can store enough energy to charge a cellphone in 20 to 30 seconds.

    “It charges very quickly and can store a lot of energy,” Khare said. “The cool thing is that it's a lot thinner than one strand of hair.”

    Khare hasn't used her invention to recharge a cellphone yet,but she used it to power a light-emitting diode (LED) in order to show its capability(容量). If used on cellphones,the supercharger would slide on to the phone's battery to juice it up in a matter of seconds. The technology isn't available to consumers yet,and it could be years until it is.

    At an Intel event in Phoenix,Khare won the Intel Foundation Young Scientist Award,taking second place overall in the world's largest high school science research competition. She beat out more than 1,600 finalists from 70 countries. She said that she has been approached by several companies to continue her research,but she is now focused on attending Harvard University in autumn.

    “Right now,just my education,but hopefully we'll see what happens in the future,” she said about her plans. “I have a lot of interests,so we'll see what I do in the future.”