首页
登录
职称英语
One of the greatest mysteries in the study of Cetacea[aquatic mammals]has al
One of the greatest mysteries in the study of Cetacea[aquatic mammals]has al
游客
2025-04-09
10
管理
问题
One of the greatest mysteries in the study of Cetacea[aquatic mammals]has always been that the creatures found in the stomachs of toothed whales show no teeth marks. Now a University of California at Santa Cruz professor thinks he may have solved the
enigma
with what he calls the "big bang" theory of cetacean predation.
Ken Norris,natural history professor,believes that rather than use their teeth to attack their victims, toothed whales stun their prey with intense bursts of sound. He points out that all 68 species of odonto-cetes(a sub-order that includes dolphins)use sound to locate their victims,and suggests this ability may have evolved to the point where it could be used as a weapon.
Millions of years ago,the ancestors of whales had a narrow tapered jaw,streamlined for speed and bristling with long rows of sharp teeth. Today odontocetes are not adapted to surprising their prey or trapping it quickly. Most are more bulky than their forebearers; their teeth are short and unevenly spaced when they exist at all. Norris suggests that because of their sonar ability,whales’ teeth have become vestigial, like the human appendix.
It is difficult to test the big bang theory because in captivity,cetaceans tend to
moderate
their sonar so as not to deafen other creatures in their small,highly reflective tanks. Dolphins are known to politely turn off their echolocation systems when passing one another. And in the wild it’ s hard to tell whether a sound came from a nearby animal or form another very far away.
But Norris points to the male narwhal as tacit proof of his theory. This whale has no teeth,and the single spiral tusk that extends about eight feet in front of him would seem to be more of an impediment than an aid in catching shrimp,his preferred feed. "You look at these animals and you wonder what’s going on." [br] The underlined word
enigma
means_____.
选项
A、debate
B、fact
C、mystery
D、proof
答案
C
解析
enigma的意思是“难于理解的问题、人、物、情况等;奥秘”,C项的“mystery“神秘,神秘的事物”与之相符。
转载请注明原文地址:https://tihaiku.com/zcyy/4033923.html
相关试题推荐
Theworld’sgreatestsportingevent,theOlympicGames,upholdstheamateuridea
OneofthegreatestmysteriesinthestudyofCetacea[aquaticmammals]hasal
OneofthegreatestmysteriesinthestudyofCetacea[aquaticmammals]hasal
Tosomepeople,thegreatestpleasureoflifeistospendtheirtimeathomewatc
Thegreatestdevastationofoldageisthelossofmentalfaculties,andwit
Thegreatestdevastationofoldageisthelossofmentalfaculties,andwit
JamesJoycewas______asthegreatestwriterofthe20thcentury.A、salutedB、esti
Thisisthe______pianoonwhichthecomposercreatedsomeofhisgreatestworks.
Thesinglegreatestshiftinthehistoryofmass-communicationtechnologyoc
Thesinglegreatestshiftinthehistoryofmass-communicationtechnologyoc
随机试题
认为利率是由商品市场与货币市场同时实现均衡条件决定的经济学派是()A.古典经
非国家所有的但对国家和社会具有保存价值的或者应当保密的档案,在向社会出卖时,应由
()是指预先分析目标偏离的可能性,并拟定和采取各项预防性措施,使计划目标得以
城镇燃气加臭剂应符合下列要求,说法错误的是()。A.加臭剂和燃气混合在一起后
以Boyden小室法能检测A.中性粒细胞的定向运动能力 B.中性粒细胞的吞噬调
下列畸形不是功能矫治器的适应证的是A.Ⅰ类错 B.Ⅱ类1分类错 C.Ⅱ类2分
下列不是构建退休规划的首要目标的是()。A.过理想的生活 B.退休后财务自由
关于氯丙嗪的叙述正确的是A.本品结构中有噻唑母核 B.氯丙嗪结构稳定,不易被氧
若进口设备采用装运港船上交货价,则卖方的责任有( )。A.负责租船订舱,支付运
A
最新回复
(
0
)