阅读下面的文字,完成下列问题。如果有人对你说:“你已经吃过转基因食品了。”(1)你可

题型:单项选择题

问题:

阅读下面的文字,完成下列问题。

如果有人对你说:“你已经吃过转基因食品了。”(1)你可能不相信。(2)但事实上,我们吃的豆油很多是由美国的转基因大豆提炼的,(3)我们平时喝的啤酒所用的菌种(酵母)也很有可能经过基因改良。(4)所以,不知不觉之中,转基因食品已经在我们体内穿肠而过了

其实如今人类享有的任何一种生物:或多或少都已经经过“基因修整”。但是,过去的千百年来,人们是通过自然基因突变来选择具有某种特定基因、特定性状的生物体,而现在的转基因技术则是通过分子生物学手段直接改变基因结构。

利用这种技术开发出来的食品,产量高、营养丰富、抗菌能力强。但是,这种技术创造出来的新型遗传基因有可能对生态环境造成难以消除的所谓遗传基因污染,最终祸害人类自身。

一般在市面上出售的转基因食品对人的健康并没有威胁,因为大部分此类食品只是改变了食品的营养结构,例如提高蛋白质含量。真正从人类的利益出发开发的转基因食品对我们是有益的。

当然,这只是就短期而言。如果以一百万年为思考范围,人会不会因为吃了营养结构改变的食品而引起生理结构的改变这样的改变对人类又有怎样的意义以“蝴蝶效应”为类比:纽约一只蝴蝶颤动翅膀,就有可能引起大洋彼岸的一场大风暴。恐龙的灭绝也有可能仅仅是因为它的主要食品中一条基因的改变。

“应该在转基因食品上贴标签,不仅仅出于安全的考虑。”专家说,“如果消费者吃了转基因食品,至少应该让他知情。消费者有选择的权利。”

转基因食品的优势在于产量高、营养丰富,对于面临资源危机的人类,尤其是人口众多、土地资源相对贫乏的中国来说,无疑是一个好消息。而且用常规技术提高粮食产量、改变食品营养结构的可能性远远不及生物技术。可以说21世纪唯一有可能解决粮食问题的就是生物技术。

但是如果从整个人类的发展来看,转基因食品未必是我们的福祉。整个生物界都是优胜劣汰进化而来,转基因食品利用的技术却不一定符合进化论原则,也许会破坏几十亿年以来的生态乎衡。从进化论角度看,生态平衡中起于青萍之末的微风有可能在进化的尺度上放大成足以毁灭物种的大风暴。

20世纪以来除了核技术之外,转基因是最有争议的科学技术之一。它是人类埋下的自我毁灭的定时百万年的炸弹抑或在不久的将来,我们在海滩享受日光浴的同时体内就自动生成了营养素希望是后者。相信随着人类对基因认识的不断深入,现存的问题会逐步解决。

对“转基因”、“基因修整”、“遗传基因污染”的理解,不正确的一项是()。

A.“转基因”指通过分子生物学手段直接改变基因结构。

B.“基因修整”指通过自然基因突变来选择具有某种特定基因、特定性状的生物体。

C.“遗传基因污染”指通过分子生物学手段直接改变基因结构对生态环境所造成的有害影响。

D.“转基因”是“基因修整”的一种方法,这种方法有可能造成“遗传基因污染”。

考点:在职联考GCT(语文)工程硕士(GCT)语文
题型:单项选择题

男性,50岁,被重物砸伤致双下肢广泛软组织挫伤,入院查心率108次/分,血压113/64mmHg,急行手术清创。此时的最佳输液原则是()。

A.使用升压剂

B.扩容,碱化尿液

C.输血

D.输血浆代用品

E.输左旋糖酐

题型:单项选择题

住房公积金不属于职工薪酬的核算范围。( )

题型:单项选择题

“ZEBRA”蓄电池的结构如图所示,电极材料多孔Ni/NiCl2和金属钠之间由钠离子导体制作的陶瓷管相隔。下列关于该电池的叙述错误的是

        

A.电池反应中有NaCl生成

B.电池的总反应是金属钠还原三个铝离子

C.正极反应为:NiCl2+2e=Ni+2Cl

D.钠离子通过钠离子导体在两电极间移动

题型:单项选择题

阅读理解。

     Solar energy for your home is coming. It can help you as a single home owner. It can help the whole

country as well. Whether or not solar energy can save your money depends on many things. Where you

live is one factor and the type of home you have is another. Things like insulation (绝缘材料), present

energy costs, and the type of system you buy are added factors.

     Using solar energy can help save our precious fuel. As you know, our supplies of oil and gas are very

limited. There is just not enough on hand to meet all our future energy needs. Sooner or later Mother Nature

will say that's all. The only way we can delay hearing those words is by starting to save energy now and

by using other sources, like the sun.

     We won't have to worry about the sun's running out of energy for another several billion years or so.

Besides, the sun doesn't offer as many problems as other energy sources. For example, fossil fuel (矿物

燃料) adds to already high pollution levels. With solar energy, we will still need sources of energy, but we

won't need as much. That means we can cut down on our pollution problems. With all these good points,

why don't we use more solar power? There are many reasons for this. The biggest reason is money. Until

now, it was just not practical for a home owner to put in a solar unit. There were cheaper sources of energy.

     All that is changing now. Solar costs are starting to equal the costs of oil and electricity. Experts say

that gas, oil and electricity prices will continue to rise. The demand for electricity is increasing rapidly. But

new power plants will use more gas, oil or coal. Already in some places the supply of electricity is being

rationed (限量供应). Solar energy is now in its infancy (初期). It could soon grow to become a major part

of our nation's energy supply.

1. What's this passage mainly about? [ ]

A. Something about solar energy and pollution.

B. Solar energy.

C. Energy and pollution.

D. Energy and money.

2. Solar energy can help us _____. [ ]

A. escape punishment from nature

B. become home owners

C. get rid of present energy

D. save our precious fuel

3. The sun is an endless source of energy, and it will not run out of energy for _____. [ ]

A. several million years

B. several hundred years

C. several billion years

D. several thousand years

4. Which of the following statements is TRUE? [ ]

A. Energy from coal would not pollute our living environment.

B. Energy from natural gas would not pollute our living environment.

C. Energy from the sun would not pollute our living environment.

D. Energy from oil would not pollute our living environment.

5. Solar energy is now in its infancy, _____. [ ]

A. but in the future it will become an important part of our nation's energy supply

B. so we will build more power plants

C. and the supply of electricity will be rationed throughout the country

D. so we don't need it

题型:单项选择题

教育心理学是研究教学环境中教与学的基本()的科学。

A.学习规律

B.教学规律

C.心理规律

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