t much hydrogen is produced. Still, the researchers see this as a first step in their goal to produce hydrogen efficiently from algae. With more work, they may be able to speed the cells' activity and produce larger quantities of hydrogen.
The researchers hope that algae will one day be an easy-to-use fuel source. The organisms are cheap to get and to feed, Ghirardi says, and they can grow almost anywhere: "You can grow them in a reactor, in a pond. You can grow them in the ocean. There's a lot of flexibility in how you can use these organisms."
36. What does the writer say about plants concerning solar energy?
A Plants are the real experts in producing solar energy.
B Plants have been used to produce solar energy.
C Plants have been using solar energy for billions of years.
D Plants have been a source of solar energy.
37. Why do some scientists study how plants convert sunlight carbon dioxide, and water into sugars and starches?
A Because they want algae to produce sugars and starches.
B Because they want green plants to become a new source of energy.
C Because they want to turn plant sugars to a new form of energy.
D Because they want to make photosynthesis more efficient.
38. According to the fifth paragraph, under what conditions are algae able to use solar energy to make hydrogen?
A When there is a lot of oxygen in the air.
B When there is no oxygen in the air.
C When photosynthesis is taking place.
D When enough starch is stored.
39. Researchers have met with difficulties when trying to make algae produce hydrogen efficiently. Which one of the following is one such difficulty?
A It is not possible to remove sulfate from the environment.
B It is not possible to work in an airfree environment to produce hydrogen.
C It is not easy to make sugars instead of hydrogen.
D It is too slow for algae to produce hydrogen when the sulfate is removed.
40. What is NOT true of algae?
A They are easy to grow.
B They can be a very good fuel source.
C They are cheap to eat.
D They can be used in many ways.
第三篇 Clone Farm
Factory farming could soon enter a new era of mass production. Companies in the US are developing the technology needed to “clone” chickens on a massive scale. Once a chicken with desirable traits has been bred or genetically engineered, tens of thousands of eggs, which will hatch into identical copies, could roll off the production lines every hour. Billions of clones could be produced each year to supply chicken farms with birds that all grow at the same rate, have the same amount of meat and taste the same.
This, at least, is the vision of the US’s National Institute of Science and Technology, which has given Origen Therapeutics of Burlingame, California, and Embrex of North Carolina $4.7 million to help fund research. The prospect has alarmed animal welfare groups, who fear it could increase the suffering of farm birds.
That’s unlikely to put off the poultry industry, however, which wants disease resistant birds that grow faster on less food. “Producers would like the same meat quantity but to use reduced inputs to get there,” says Mike Fitzgerald of Origen. To meet this demand, Origen aims to “create an animal that is effectively a clone”, he says. Normal cloning doesn’t work in birds because eggs can’t be removed and implanted, Instead, the company is trying to bulk-grow embryon
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