首页
登录
职称英语
One of the mysteries of nature is animal communication. Creatures of the s
One of the mysteries of nature is animal communication. Creatures of the s
游客
2023-11-23
12
管理
问题
One of the mysteries of nature is animal communication. Creatures of the sea move through their liquid element without any hearable sound. Yet they are able to sense the silent passing or attack of others of their kind. This is because bodies moving in water create a pressure wave, something like a gust of wind produced by a passing automobile. A narrow sensor system running along each side of the shark, from eye to tail, receives and interprets these pressure waves. I have seen sharks appear swiftly, obviously drawn by the motion of a diver’s hands, which had sent out strong waves.
One might think it impossible to distinguish odors in water. Yet sharks, surprisingly, are able to follow a scent across miles of ocean and arrive at its exact source. A diver who spears a fish and attaches its bloody body to his belt, and then goes on with the hunt, be comes a natural prey to the shark. I have seen sharks follow a scent exactly like the dogs of a hunting pack. It is no wonder th at the Greeks gave them the name "hounds of the sea."
One of the most widely believed — and dangerous — legends about the shark is that he has poor eyesight. On the contrary, the shark is well equipped to see at a distance and to dis tinguish among forms. This fact was proved to me one day when I went into the water off the coast of Africa. I sighted a shark at some distance from me as I was floating at a very shallow depth. Since I was making no movement, the sound of bubbles from my diving appa- ratus would be confused with the light splashing of the water on a rock. I turned my eyes away for a few seconds, to study the design of a giant ray just beneath me. I am not sure now whether it was simple instinct or a feeling of movement, but I turned back abruptly to ward the location of the shark. And, immediately, every muscle of my body tensed. He was no more than 30 feet away, launched toward me as hard and swift as a missile.
The sight of a shark coming at you head-on is strange. Obviously it is from this angle that he seems most frightening-the very symbol of evil, with the half-opened mouth and the three regularly spaced fins (鳍). When the shark had approached to within two feet of the rubber fins I had thrown at him as a gesture of self-defense, he turned suddenly and swam back toward the depths. There had been no sound, no scent. It appears certain that sight alone was responsible for this approach. [br] There is a misunderstanding that___________.
选项
A、sharks can discover a diver by the movement of his hands in water
B、sharks have very strong sense of smell
C、sharks have poor eyesight
D、sharks are great threats to divers
答案
C
解析
转载请注明原文地址:https://tihaiku.com/zcyy/3213453.html
相关试题推荐
Thatlargeanimalsrequirealuxuriantvegetation,hasbeenageneralass
Thatlargeanimalsrequirealuxuriantvegetation,hasbeenageneralass
Thatlargeanimalsrequirealuxuriantvegetation,hasbeenageneralass
Thatlargeanimalsrequirealuxuriantvegetation,hasbeenageneralass
Thatlargeanimalsrequirealuxuriantvegetation,hasbeenageneralass
Wildlifeconservationistssaythecoverthatfoliageprovidesforanimalsisequ
Thenatureofworkischanging.Recenttechnologicaladvances,ashiftfrom
Thenatureofworkischanging.Recenttechnologicaladvances,ashiftfrom
Thenatureofworkischanging.Recenttechnologicaladvances,ashiftfrom
Thenatureofworkischanging.Recenttechnologicaladvances,ashiftfrom
随机试题
实施CI战略,树立运输企业良好的企业形象应注重()方面的管理。A.明确社会责
对于中毒型菌痢脑型和乙脑的鉴别最有意义的是()A.起病急骤 B.大便检查
属于核苷酸还原酶抑制剂的是A.巯嘌呤 B.利妥昔单抗 C.羟基脲 D.氟尿
运用风险管理工具进行风险控制的方法包括()。 A.建立损失准备金 B.转移
2014年1月1日起,将铁路运输业和邮政服务业纳入“营改增”试点。至此,交通运输
下列属于行政机关处理的行政争议能够进行仲裁的是()。A.婚姻纠纷 B.合同纠纷
水利系统文明建设工地安全管理标准有()。A.施工安全事故处置方案 B.安全生
男性,42岁,自幼起咳嗽、咳痰、喘息,多为受凉后发作,静滴"青霉素"可缓解,10
电解质
马斯洛需要层次论最低层次的需要是() A.尊重的需要 B.生理的需要 C.
最新回复
(
0
)