Plant Gas Scientists have been studying natural sources of methane for decarlesd but h - 试题答案网问答

第1题

Plant Gas Scientists have been studying natural sources of methane for decades but hadn

Plant Gas

Scientists have been studying natural sources of methane for decades but hadn't regarded plants as a producer,notes Frank Keppler,a geochemist at the Max Planck Institute for Nuclear Physics in Hei- delberg,Germany. Now Keppler and his colleagues find that plants,from grasses to trees,may also be sources of the greenhouse gas. This is really surprising, because most scientists assumed that methane production requires an oxygen-free environment. .

Previously, researchers had thought that it was impossible for plants to make significant amounts of the gas. They had assumed that,microbes need to be in environments without oxygen to produce methane. Methane is a greenhouse gas,like carbon dioxide. Gases such as methane and carbon dioxide trap heat in Earth's atmosphere and contribute to global warming.

In its experiments,Keppler's team used sealed chambers that contained the same concentration of oxygen that Earth's atmosphere has. They measured the amounts of methane that were released by both living plants and dried plant material,such as fallen leaves. '

With the dried plants, the researchers took measurement at temperatures ranging from 30 degrees oC elsius t0 70 degrees 'C. At 30 degrees oC ,they found,a gram of dried plant material released up t0 3 nanograms of methane per hour. (One nanogram is a billionth of a gram. ) With every lO-degree rise in temperature,the amount of methane released each hour roughly doubled.

Living plants growing at their normal temperatures released as much as 370 nanograms of meth- ane per gram of plant tissue per hour. Methane emissions tripled when living and dead plant was ex- posed to sunlight.

Beeause there was plenty of oxygen available,it's unlikely that the types of bacteria that normally make methane were involved. Experiments on plants that were grown in water rather than soil also re- sulted in methane emissions. That's another strong sign that the gas came from the plants and not soil microbes.

The new finding is an "interesting observation," says Jennifer Y. King, a biogeochemist at.the University of Minnesota in St. Paul. Because some types of soil microbes consume methane,they may prevent plant-produced methane from reaching the atmosphere. Field tests will be needed to assess the plant's influence, she notes.

What was scientists understanding of methane？

A.It was produced from plants

B.It was not a greenhouse gas

C.It was produced in oxygen-free environments

D.It traps more heat than any other greenhouse gas

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第2题

Plant GasScientists have been studying natural sources of methane （甲烷，沼气) for decades

Plant Gas

Scientists have been studying natural sources of methane (甲烷，沼气) for decades but hadn't regarded plants as a producer, notes Frank Keppler, a geochemist(地球化学家) at the Max Planek Institute for Nuclear Physics in Heidelberg, Germany. Now Keppler and his colleagues find that plants, from grasses to trees, may also be sources of the greenhouse gas. This is really surprising, because most scientists assumed that methane production requires an oxygen-free environment.

Previously, researchers had thought that it was impossible for plants to make significant amounts of the gas. They had assumed that microbes(微生物) need to be in environments without oxygen to produce methane. Methane is a greenhouse gas, like carbon dioxide. Gases such as methane and carbon dioxide trap heat in Earth's atmosphere and contribute to global warming.

In its experiments, Keppler's team used sealed chambers (室，房间；腔) that contained the same concentration of oxygen that Earth's atmosphere has. They measured the amounts of methane that were released by both living plants and dried plant material, such as fallen leaves.

With the dried plants, the researchers took measurement at temperatures ranging from 30 degrees Celsius to 70 degrees C..At 30 degrees C., they found, a gram of dried plant material released up to 3 nanograms(微克) of methane per hour (One nanogram is a billionth of a gram. ). With every 10-degree rise in temperature, the amount of methane released each hour roughly doubled.

Living plants growing at their normal temperatures released as much as 370 nanograms of methane per gram of plant tissue per hour. Methane emissions tripled (增加三倍) when living and dead plant was exposed to sunlight.

Because there was plenty of oxygen available, it's unlikely that the types of bacteria(bacterium 的复数，细菌) that normally make methane were involved. Experiments on plants that were grown in water rather than soil also resulted in methane emissions. That's another strong sign that the gas came from the plants and not soil microbes.

The new finding is an "interesting observation," says Jennifer Y.King, a biogeochemist(生物地球化学家) at the University of Minnesota in St. Paul. Because some types of soil microbes consume methane, they may prevent plant-produced methane from reaching the atmosphere. Field tests will be needed to assess the plant's influence, she notes.

What was scientists' understanding of methane？

A．It was produced from plants.

B．It was not a greenhouse gas.

C．It was produced in oxygen-free environments.

D．It traps more heat than any other greenhouse gas.

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第3题

请根据短文内容，回答题。 Plant GasScientists have been studying natural sources of methane f

请根据短文内容，回答题。

Plant Gas

Scientists have been studying natural sources of methane for decades but hadn&39;t regarded plants as a producer, notes Frank Keppler, a geochemist at the Max Planck Institute for Nuclear Physics in Heidelberg, Germany. Now Keppler and his colleagues find that plants, from grasses to trees, may also be sources of the greenhouse gas. This is really surprising, because most scientists assumed that methane production requires an oxygen-free environment.＜br＞

Previously, researchers had thought that it was impossible for plants to make significant amounts of the gas. They had assumed that microbes need to be in environments without oxygen to produce methane. Methane is a greenhouse gas, like carbon dioxide. Gases such as methane and carbon dioxide trap heat in Earth&39;s atmosphere and contribute to global warming.＜br＞

In its experiments, Keppler&39;s team used sealed chambers that contained the same concentration of oxygen that Earth&39;s atmosphere has. They measured the amounts of methane that were released by both living plants and dried plant material, such as fallen leaves.＜br＞

With the dried plants, the researchers took measurement at temperatures ranging from 30 degrees Celsius to 70 degrees C. At 30 degrees C, they found, a gram of dried plant material released up to 3 nanograms of methane per hour. (One nanogram is a billionth of a gram.) With every 10-degree rise in temperature, the amount of methane released each hour roughly doubled.＜br＞

Living plants growing at their normal temperatures released as much as 370 nanograms of methane per gram of plant tissue per hour. Methane emissions tripled when living and dead plant was exposed to sunlight.＜br＞

Because there was plenty of oxygen available, it&39;s unlikely that the types of bacteria that normally make methane were involved. Experiments on plants that were grown in water rather than soil also resulted in methane emissions. That&39;s another strong sign that the gas came from the plants and not soil microbes.＜br＞

The new finding is an "interesting observation," says Jennifer Y. King, a biogeochemist at the University of Minnesota in St. Paul. Because some types of soil microbes consume methane, they may prevent plant-produced methane from reaching the atmosphere. Field tests will be needed to assess the plant&39;s influence, she notes.

What was scientists‘ understanding of methane？查看材料

A.It was produced from plants

B.It was not a greenhouse gas

C.It was produced in oxygen-free environments

D.It traps more heat than any other greenhouse gas

点击查看答案

第4题

Plant GasScientists have been studying natural sources of methane for decades but hadn't r

Plant Gas

Scientists have been studying natural sources of methane for decades but hadn't regarded plants as a producer, notes Frank Keppler, a geochemist at the Max Planck Institute for Nuclear Physics in Heidelberg, Germany. Now Keppler and his colleagues find that plants, from grasses to trees, may also be sources of the greenhouse gas. This is really surprising, because most scientists assumed that methane production requires an oxygen-free environment.

Previously, researchers had thought that it was impossible for plants to make significant mounts of the gas. They had assumed that microbes need to be in environments without oxygen to produce methane. Methane is a greenhouse gas, like carbon dioxide. Gases such as methane and carbon dioxide trap heat in Earth's atmosphere and contribute to global warming.

In its experiments, Keppler's team used sealed chambers that contained the same concentration of oxygen that Earth's atmosphere has. They measured the amounts of methane that were released by both living plants and dried plant material, such as fallen leaves.

With the dried plants, the researchers took measurement at temperatures ranging from 30 degrees Celsius to 70 degrees C. At 30 degrees C, they found, a gram of dried plant material released up to 3 nanograms of methane per hour. (One nanogram is a billionth of a gram. ) With every 10-degree rise in temperature, the amount of methane released each hour roughly doubled.

Living plants growing at their normal temperatures released as much as 370 nanograms of methane per gram of plant tissue per hour. Methane emissions tripled when living and dead plant was exposed to sunlight.

Because there was plenty of oxygen available, it's unlikely that the types of bacteria that normally make methane were involved. Experiments on plants that were grown in water rather than soil also resulted in methane emissions. That's another strong sign that the gas came from the plants and not soil microbes.

The new finding is an "interesting observation," says Jennifer Y. King, a biogeochemist at the University of Minnesota in St. Paul. Because some types of soil microbes consume methane, they may prevent plant-produced methane from reaching the atmosphere. Field tests will be needed to assess the plant's influence, she notes.

What was scientists' understanding of methane？

A．It was produced from plants.

B．It was not a greenhouse gas.

C．It was produced in oxygen-free environments.

D．It traps more heat than any other greenhouse gas.

点击查看答案

第5题

According to scientists, to keep down concentrations of greenhouse gases, we should ______

.

A．stop gas emissions

B．lower the temperature

C．reduce the use of coal, oil, and gas

D．cut off the use of coal, oil, and gas

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第6题

Scientists from many countries agree that the recent warming is caused in part by such hum

an activities as man's ever-increasing consumption of gas or oil.

A．Y

B．N

C．NG

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第7题

To test whether plants are a source of methane, the scientists created ______.A．a oxygen-f

To test whether plants are a source of methane, the scientists created ______.

A．a oxygen-free environment

B．an environment with the same concentration of oxygen as the Earth has

C．a carbon dioxide-free environment

D．an environment filled with the greenhouse gas

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第8题

Scientists study how photosynthesis works because they want to __________.

查看材料

A.improve the efficiency of it

B.turn plant sugars to a new form. of energy

C.make green plants a new source of energy

D.get more sugars and starches from plants

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第9题

The pollution of Hong Kong's beaches by oil from a damaged tanker last year recalls a simi

lar incident which took place in Britain in 1967 when the Torrey Canyon, a huge oil tanker, split in two and caused disaster in coastal areas. Shoals of fishes were killed, sea birds hopelessly fouled with oil and coastal holiday resorts put out of business for several weeks. As a result of this particular incident scientists are becoming restless at the thought of Britain’s inability to cope with national disasters on a large scale. The reason for their concern is that technology is rapidly outstripping (超越) man's ability to control it.

Oil tankers, for instance, have been allowed to get bigger and bigger without sufficient thought being given to emergency braking and maneuvering arrangement. Collisions at Sea continue, but little effect has been made to develop safety devices as effective as those used for aircraft.

Scientists were outspoken in expressing their concern during a recent meeting of the British Association. Unanimous approval was voiced when the leading speaker urged that a permanent national rescue services should be established, equipped for any emergency and ready to move off immediately.

of all the possible disasters mentioned, the one promoting most discussion was a major release of radioactivity from a nuclear power station. one does not need a particularly vivid imagination to visualize the other possibilities discussed. What would be the effect of a jumbo-jet crashing on a large chemical plant handling destroying liquids？ Could the tapping of natural gas lead to any form. to collapse？ Suppose a lorry full of a highly poisonous chemical crashed unseen into a large reservoir？ Dams can burst, abnormal conditions can lead to massive electrical blackouts.

An intensive study of such possibilities could at least reduce the effects of future disasters. For example, it would mean that a number of technical alternatives (such as the choice between detergent or chalk for dispersing oil) could be examined and tested in advance so that specially trained expert would know exactly what action was needed in a given emergency.

The main idea of the second paragraph is that ______

A．safety precautions in aircraft are not as effective as those used on ships

B．modern oil tankers can stop or turn easily in spite of their size

C．there are now fewer collisions at sea because of modem safety devices

D．oil tankers are so big that special devices are needed

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第10题

It can be inferred from the passage that scientists are "perplexed by the means" （line 12)

It can be inferred from the passage that scientists are "perplexed by the means" (line 12) for which of the following reasons？

A．They are unsure of how alanine remains separate from the everyday nitrogen metabolism of the plant itself.

B．They have yet to establish what function the alanine serves for the soybean plants.

C．They have thought alanine to exist only in very small quanties in rhizobia.

D．They have long considered the membranes of the soybean plant impermeable to amino acids.

E．They are uncertain how such a rapid export of fixed nitrogen is possible through the soybean membranes.

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