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Sea Horses
Sea horses are unusual parents. The female sea horses lay the eggs, but unlike other creatures,it&39;s the males that give birth to the young.
Male sea horses have a fold of skin on their bellies that forms pocket, called a brood pouch.
During the breeding season, the sea horse&39;s pouch swells to receive eggs. A female sea horse lays up to 200 eggs at a time in the pouch. Then she swims off, leaving her male partner to care for the developing eggs and give birth to young sea horses. The female will return everyday to check on her mate and the eggs, but she doesn&39;t stay long, nor does she take part in the birth.
It takes from two to six weeks for the eggs in the male&39;s pouch to develop. During this time the male avoids open water and hides in sea grass. His big pouch makes it difficult for him to swim,so the male often uses his tail to grasp a piece of sea grass. Firmly gripping the grass, he will stay perfectly still for hours or even days. The male sea horse will change his color to blend with his surroundings and avoid being seen by predators who will try to eat him or poke holes in his pouch to get the eggs.
The eggs hatch inside the male&39;s pouch. When the babies begin moving around, the male sea horse knows it&39;s time for them to be born. He grabs a sea grass stem with his tail and begins rocking, bending, and stretching his body so that the rest of the babies can be born. Sometimes he has to press his pouch against a rock or some stiff seaweed to force the young out.
Sea horse babies are born in groups of five or more. Sometimes it takes two days for the father sea horse to give birth to all his young. He is very tired when it&39;s over.
Soon after giving birth to one brood, the male will approach his mate and show her his empty pouch. This tells her he is ready to receive eggs again.
What part does the female sea horse play in having babies? 查看材料
A.Receiving eggs
B.Laying eggs
C.Hatching eggs
D.Protecting eggs
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Mobile Phones

Mobile phones should carry a label if they proved to be a dangerous source of radiation, according to Robert Bell, a scientist. And no more mobile phone transmitter towers should be built until the long-term health effects of the electromagnetic radiation they emit are scientifically evaluated, he said. "Nobody&39;s going to drop dead overnight but we should be asking for more scientific information," Robert Bell said at a conference on the health effects of low-level radiation.(46)
A report widely circulated among the public says that up to now scientists do not really know enough to guarantee there are no ill-effects on humans from electromagnetic radiation. According to Robert Bell, there are 3.3 million mobile phones in Australia alone and they are increasing by 2,000 a day.(47)
As well, there are 2,000 transmitter towers around Australia, many in high density residential areas.(48)The electromagnetic radiation emitted from these towers may have already produced some harmful effects on the health of the residents nearby.
Robert Bell suggests that until more research is completed the Government should ban construction of phone towers from within a 500 metre radius of school grounds, child care centres, hospitals, sports playing fields and residential areas with a high percentage of children.(49)He adds that there is also evidence that if cancer sufferers are subjected to electromagnetic waves the growth rate of the disease accelerates.
(50)According to Robert Bell, it is reasonable for the major telephone companies to fund it. Besides, he also urges the Government to set up a wide-ranging inquiry into possible health effects.
(46)
A.He says there is emerging evidence that children absorb low-level radiation at a rate more than three times that of adults.B.By the year 2000 it is estimated that Australia will have 8 million mobile phones: nearly one for every two people.C."If mobile phones are found to be dangerous, they should carry a warning label until proper shields can be devised," he said.D.Then who finances the research?E.For example, Telstra, Optus and Vodaphone build their towers where it is geographically suitable to them and disregard the need of the community.F.The conclusion is that mobile phones brings more harm than benefit.
(47)
A.He says there is emerging evidence that children absorb low-level radiation at a rate more than three times that of adults.B.By the year 2000 it is estimated that Australia will have 8 million mobile phones: nearly one for every two people.C."If mobile phones are found to be dangerous, they should carry a warning label until proper shields can be devised," he said.D.Then who finances the research?E.For example, Telstra, Optus and Vodaphone build their towers where it is geographically suitable to them and disregard the need of the community.F.The conclusion is that mobile phones brings more harm than benefit.
(48)
A.He says there is emerging evidence that children absorb low-level radiation at a rate more than three times that of adults.B.By the year 2000 it is estimated that Australia will have 8 million mobile phones: nearly one for every two people.C."If mobile phones are found to be dangerous, they should carry a warning label until proper shields can be devised," he said.D.Then who finances the research?E.For example, Telstra, Optus and Vodaphone build their towers where it is geographically suitable to them and disregard the need of the community.F.The conclusion is that mobile phones brings more harm than benefit.
(49)
A.He says there is emerging evidence that children absorb low-level radiation at a rate more than three times that of adults.B.By the year 2000 it is estimated that Australia will have 8 million mobile phones: nearly one for every two people.C."If mobile phones are found to be dangerous, they should carry a warning label until proper shields can be devised," he said.D.Then who finances the research?E.For example, Telstra, Optus and Vodaphone build their towers where it is geographically suitable to them and disregard the need of the community.F.The conclusion is that mobile phones brings more harm than benefit.
(50)
A.He says there is emerging evidence that children absorb low-level radiation at a rate more than three times that of adults.B.By the year 2000 it is estimated that Australia will have 8 million mobile phones: nearly one for every two people.C."If mobile phones are found to be dangerous, they should carry a warning label until proper shields can be devised," he said.D.Then who finances the research?E.For example, Telstra, Optus and Vodaphone build their towers where it is geographically suitable to them and disregard the need of the community.F.The conclusion is that mobile phones brings more harm than benefit.
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