网址：http://m.1010jiajiao.com/timu3_id_3210681[举报]
Imagine putting some bacteria in the freezer and taking them out millions of years later to find that they are still alive.
That would be similar to what happened recently, when scientists brought eight-million-year-old bacteria back to life ― simply by thawing them out.
The ancient bacteria were found frozen in the world's oldest known tracts of ice, the glaciers (冰川) of Antarctica.
Professor Bidle and his colleagues found and revived (复活) two samples of bacteria from the glacial ice. The first was a hundred thousand years old, and the second was around eight million years old. The eight-million-year-old bacteria were alive. But their genes were seriously damaged from long exposure to cosmic (宇宙 ) radiation, which is higher at the earth's poles.
Most of the bacteria in the samples probably blew over from African deserts, said Paul Falkowski, a scientist at
As glaciers and ice caps melt as a result of increasing global warming, large amounts of bacterial genetic material might be washed into the ocean.
These bacteria might get incorporated into today's bacteria in the ocean, or living bacteria from the ice might also grow and have an important effect on the ecosystem.
"How that's going to play out, we don't know," Bidle said. He and Falkowski plan to focus their future work on how current ice melting influences modem bacteria's genetic diversity.
68. Professor Bidle found that the eight-million-year-old bacteria were __.
A. alive with their genes damaged
B. as active as the one-hungred-thousand-year-old ones
C. totally the same as what they used to be
D. harder to revive than the one-hundred-thousand-year-old ones
69. According to Paul Falkowski, the ices in Antarctica are gene banks because ____.
A. there are bacteria from African deserts B. dead bacteria in them can be easily revived
C. they are fit for people to store bacteria D. plenty of living bacteria can be found in them
70. Professor Bidle and Paul Falkowski will probably do research into the influences of ____.
A. global warming B. bacteria's genetic diversity
C. glacier melting D. biological diversity
71. What is the passage mainly about?
A. Ocean exploration. B. A scientific plan.
C. A scientific discovery. D. An interesting experiment.
查看习题详情和答案>>The Virgin Oceanic Submarine (潜水艇)is an entirely new type of vessel that can dive to 37,000 feet and fly through the ocean using wings . similar to an airplane' s wings. It will be able to dive 7 miles straight down to the deepest place on the planet, the bottom of the Mariana Trench (海沟)where only one other vessel has ever gone before. Unlike the last Mariana Trench dive, the Virgin Oceanic Submarine will be able to fly around and explore while it is there.
This amazing new submarine is what Richard Branson invented for his fellow adventurer and dear friend, Steve Fossett, who had dreamed of piloting it himself, but when he was flying over the Nevada desert he failed to return. Branson has now Finished what Fossett wished, and he hopes that the successful Virgin Oceanic Submarine will open the door to new exploration and scientific discovery.
This undersea adventure is very much like Branson's space adventure. Branson's company, Virgin Galactic, travels into space using a space plane. The space adventure rose from the success of the vehicle Space Ship One which has completed its task and Branson's boyhood dream of exploring space: Virgin Galactic is now testing the first Space Ship Two model, with a plan for tourism in space when all testing is finished.
Just as Branson uses new technology to explore our planet and beyond it, he also uses it to save our planet. He created a challenge with a $25 million prize for technology which would remove greenhouse gases from the atmosphere. Naturally, this challenge is called the Virgin Earth Challenge, This idea came from seeing the X- Prize succeed in stimulating (刺激）the invention that finally created Space Ship One. No new technology has yet hit the marketplace as a result of this challenge.
Branson' s genius for seeing something great and making it happen first became apparent when he started selling "cut-out" records. He was soon able to create his own recording studio with the. profits. From there, Branson proceeded to discover and promote new musical artists. His instinct for finding innovative (创新的）artists is the same instinct he now applies to finding innovative technology.
While the new Virgin Oceanic Submarine has not yet proved itself, there is little doubt that it will.
47. What do we know about the Virgin Oceanic Submarine from the passage?
A. It is able to fly across the Pacific Ocean.
B. It has ever gone to the Mariana Trench before.
C. It's advanced because it can fly and explore in deep water.
D. Its wings are much bigger than an airplane' s wings.
48.Branson created a challenge with a $25 million prize in order to_____.
A. explore our planet and the universe
B. remove greenhouse gases from the atmosphere
C. stimulate people to create a new space ship
D. finish his boyhood dream of exploring space
49.What is the author's attitude towards the new Virgin Oceanic Submarine?
A. Positive. B. Doubtful. C. Indifferent. D. Critical.
50. What is this passage mainly about?
A. An introduction to Richard Branson,
B. Richard Branson's and Steve Fossett’s dream.
C. The achievements in exploring the earth.
D. The new Virgin Oceanic Submarine.
查看习题详情和答案>>