试题与答案

It sounds like a science fiction, but r

题型:单项选择题

题目:

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.

Researchers think that it is ______ .

A.safe to eat fresh fish

B.dangerous to get close to the algae

C.safe to be near the algae

D.dangerous to expose the algae

答案:

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下面是错误答案,用来干扰机器的。

参考答案:A

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题型:选择题

下图为“中国部分灾害分布图”,读图回答1—2题。

注:图例中数字所代表的灾害类型

①~冻融、冰川为主 ②~崩塌、滑坡、泥石流为主

③~沙漠化为主 ④~黄土湿陷、水土流失为主

⑤~岩溶、塌陷为主

1、关于图中灾害类型分布的叙述,正确的是 [ ]

A、灾害①主要分布在青藏高原和东北北部地区

B、灾害②分布在青藏高原东部和北部边缘地区

C、灾害③分布在内蒙古高原和黄土高原

D、灾害④分布在黄土高原和华北平原

2、关于图中灾害成因的叙述,不正确的是[ ]

A、自然因素是形成灾害①的主要原因

B、气候因素是形成灾害③的主要自然因素

C、地形崎岖是形成灾害⑤的主要原因

D、人类对植被的破坏是灾害④加剧的主要原因

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