It sounds like a science fiction, but researchers say it’s a scientific fact

游客2023-12-27  12

问题     It sounds like a science fiction, but researchers say it’s a scientific fact: Microscopic organisms dubbed "killer algae" are paralyzing fish with unknown toxins and then eating away at their flesh. They might be making people sick, too.
    The name given to this single-cell organism, or dinoflagellate, is Pfiesteria piscimorte—literally, "fish killer." It was discovered at North Carolina State University in 1988, but at the same time, few scientists believed in its existence, much less in its highly unusual predatory nature. But ongoing research has led to international acknowledgment of the phenomenon and, recently, research funding.
    Seemingly prompted by an unknown substance secreted by fish, the aggressive creature swims into action. It sends neurotoxins into the water and air, paralyzing a fish’s nervous system, and causing it to gasp for air at the surface. Eventually the fish suffocates. The killer dinoflagellate then attaches itself to the fish and begins sucking away at its flesh. This macabre scenario may help solve several sea mysteries, such as why fishermen report seeing "fish walks" (fish trying to leave the water) and pools of dead fish with holes eaten through them.
    Whether humans are affected by the dinoflagellate’s toxin remains to be seen. Researchers think it’s unlikely eating fresh fish are in danger, but anyone with frequent exposure to the creature could be in peril. Several researchers working with the algae have reported bouts of memory loss and disorientation.
    To understand the killer algae further, scientists must fully characterize their toxin and determine what stimulates them to attack. They also need to know if the algae are hurting fish populations, and whether pollutants make them more likely to attack. [br] Which of the following questions is answered according to the information given in the passage?

选项 A、What is the toxin used by the fish killer?
B、Who first discovered the organism?
C、How does the fish killer paralyze fish?
D、How many fishes can the organism kill each day?

答案 C

解析 是非题型第一段中提到the fish killer有toxins,但没提它使用何种toxins,排除选项A;第二段中提到the fish killer于1988年在大学被发现,但没提及是谁发现的,排除选项B;选项D在文中没有提及;因此C为答案(在第三段第二句中谈到the fish killer向水中、空气中释放神经毒素,麻痹了鱼类的神经系统,使得鱼类钻到水面呼吸;最终鱼类窒息而死;然后它就附着于鱼身食其肉)。
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