首页
登录
职称英语
It is hard to track the blue whale, the ocean’s largest creature, which has
It is hard to track the blue whale, the ocean’s largest creature, which has
游客
2023-11-21
23
管理
问题
It is hard to track the blue whale, the ocean’s largest creature, which has almost been killed off by commercial whaling and is now listed as an endangered species. Attaching radio devices to it is difficult, and visual sightings are too unreliable to give real insight into its behavior.
So biologists were delighted early this year when, with the help of the Navy, they were able to track a particular blue whale for 43 days, monitoring its sounds. This was possible because of the Navy’s formerly top-secret system of underwater listening devices spanning the oceans.
Tracking whales is but one example of an exciting new world just opening to civilian scientists after the cold war as the Navy starts to share and partly uncover its global network of underwater listening system built over the decades to track the ships of potential enemies.
Earth scientists announced at a news conference recently that they had used the system for closely monitoring a deep-sea volcanic eruption for the first time and that they plan similar studies.
Other scientists have proposed to use the network for tracking ocean currents and measuring changes in ocean and global temperatures.
The speed of sound in water is roughly one mile a second--slower than through land but faster than through air. What is most important, different layers of ocean water can act as channels for sounds, focusing them in the same way a stethoscope does when it carries faint noise from a patient’ s chest to a doctor’ s ear. This focusing is the main reason why even relatively weak sounds in the ocean, especially low-frequency ones, can often travel thou- sands of miles. [br] The underwater listening system was originally designed ______.
选项
A、to trace and locate enemy vessels
B、to monitor deep-sea volcanic eruptions
C、to study the movement of ocean currents
D、to replace the global radio communications network
答案
A
解析
根据第三段的“…its global network of underwater listening system built over the decades to track the ships of potential enemies.”,可以看出这套系统最初是为了“trace and locate enemy vessels”而建立的,所以,A 符合题意。
转载请注明原文地址:https://tihaiku.com/zcyy/3207273.html
相关试题推荐
Oneofthemysteriesofnatureisanimalcommunication.Creaturesofthes
Oneofthemysteriesofnatureisanimalcommunication.Creaturesofthes
Oneofthemysteriesofnatureisanimalcommunication.Creaturesofthes
Itishardtotrackthebluewhale,theocean’slargestcreature,whichhas
Thepassagetellsusthatcats___________.[originaltext]Catsarecreatures
Certainlynocreatureintheseaisodderthanthecommonseacucumber.All
Certainlynocreatureintheseaisodderthanthecommonseacucumber.All
Certainlynocreatureintheseaisodderthanthecommonseacucumber.All
Outdooradvertisingprovidestheadvertiserwiththelargestcolourfuldisplay
Certainlynocreatureintheseaisodderthanthecommonseacucumber.All
随机试题
Peter,whomeveryonesuspected,______tobeinnocent.A、turnedoutB、turnedoffC
WhydidTinacometotheemploymentagency?Tolookfor______.[br][originalte
[originaltext]CountyfairsareatraditioninNewEnglandtowns.Theyoffer
现阶段监管科技的运用主要集中于事中监管阶段,但各监管主体正在努力探索其在事前、事
幼儿园环境按其性质可分为( )和( )。A.物质环境
上市公司重大资产重组,购买资产实现利润盈利预测为4000万元,实际实现利润300
企业社会工作小组过程包括()。A.制订小组计划书 B.招募组员 C.确定目
共用题干 某商品住宅小区公有住宅800套,已售出并交付600套,其中三套住房登
根据支付结算法律制度的规定,下列关于信用卡的非现金交易的表述,正确的有()。A
交通安全设施除包括交通标志、交通标线、隔离栅、视线诱导没施、里程标、公路界碑外,
最新回复
(
0
)