首页
登录
职称英语
The majority of small tooth whales are called dolphins. Most dolphin species
The majority of small tooth whales are called dolphins. Most dolphin species
游客
2023-07-16
23
管理
问题
The majority of small tooth whales are called dolphins. Most dolphin species are about 6 ft in length, the males averaging 4 to 8 in. longer than females. The largest is the killer whale, which can be
ft long and weigh between 8000—10000 lbs. The smallest species is the buffeo, found in the Amazon River. The buffeo rarely grows over 3.9 ft in length and 66 lbs in weight.
Dolphins once were hunted commercially, especially for the small quantity of valuable oil extracted from palls of the head and used to lubricate delicate watch mechanisms. Cheaper oils have now been found from other sources, and dolphins are no longer hunted for this reason. Many dolphins, however, become accidentally trapped and drowned in tuna nets. Between the years 1959 and 1972, an estimated 4.8 million dolphins died this way. Because of the pressure from animal rights activists and the United States consumers, both domestic and international tuna canners have refused to accept shipments from fishing fleets that do not protect dolphins.
Dolphins are extremely and almost constantly vocal. They are capable of two kinds of sounds. A specialized mechanism in the nasal passage just below the blow-hole enables them to emit short, pulse-type sounds. These sounds, called clicks, can be produced in such rapid succession as to sound like a buzz or even a duck-like quack. The clicks are used as a form of sonar, in which echoes of sounds from surrounding objects enable the animals to detect obstacles, other dolphins, fish, and even tiny bits of matter in the water. The military use dolphins and this ability to help find water mines.
Deeper in the respiratory system-presumably in the larynx-dolphins produce another type of sound: a high pitched whistle of squeal, which is capable of rapid pitch changes. The whistles differ from the clicks in being essentially single tones. Apparently dolphins use the whistles to communicate a particular emotional state and thus influence the behaviour of other dolphins. Typically, the squeals denote alarm or sexual excitement. [br] Which of the following is true according to the passage?
选项
A、5 million dolphins were hunted commercially from 1959 to 1972.
B、People’s recognition of animal rights helps protect dolphins.
C、Dolphins am good at giving out sounds.
D、Clicks are used by dolphins to influence other dolphins’ behaviour.
答案
B
解析
转载请注明原文地址:https://tihaiku.com/zcyy/2842594.html
相关试题推荐
Researchershaveidentified1.4millionanimalspeciessofar—andmillions
Researchershaveidentified1.4millionanimalspeciessofar—andmillions
Researchershaveidentified1.4millionanimalspeciessofar—andmillions
Researchershaveidentified1.4millionanimalspeciessofar—andmillions
[originaltext]In1967,AmericanVoguemagazinepublishedanarticlecalled
[originaltext]In1967,AmericanVoguemagazinepublishedanarticlecalled
CaliforniahasanewprogramcalledtheDigitalTextbookInitiative."Starti
CaliforniahasanewprogramcalledtheDigitalTextbookInitiative."Starti
Topuniversitieshavebeencalledontopublishlistsof"banned"A-levelsu
Topuniversitieshavebeencalledontopublishlistsof"banned"A-levelsu
随机试题
[originaltext]MynameisNickVujicic.IwasborninAustraliain1982,and
Slaverywaslegalforover200yearsinsomepartsofNorthAmerica,particu
()处罚条款()财务报表[br]()广告手册()会议记录D,E
中央银行提高再贴现率会导致货币供给量的增加和利息率的降低。()
糖尿病代谢异常不包括A.血中酮体升高 B.血脂异常 C.尿潴留 D.多尿
患者,男,56岁。左下后牙自发性搏动疼痛4天,口含冰块可暂时缓解。检查:左下7远
急性胰腺炎病人血清脂肪酶升高是在起病后A.0~4小时 B.6~12小
学生是权利的主体,其享有的法律规定的社会权利包括:_____的权利、受教育的权利
则x=0是f(x)的: A.可去间断点B.跳跃间断点 C.振荡间断点D.
细胞膜在静息情况下,对下列离子通透性最大的是A.Na B.K C.Cl D
最新回复
(
0
)