首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Since the Hawaiian Islands have never been connected to other landmasses, the great variety of plants in Hawaii must be a result
Since the Hawaiian Islands have never been connected to other landmasses, the great variety of plants in Hawaii must be a result
admin
2013-01-28
128
问题
Since the Hawaiian Islands have never been connected to other landmasses, the great variety of plants in Hawaii must be a result of the long-distance dispersal of seeds, a process that requires both a method of transport and an equivalence between the ecology of the source area and that of the recipient area.
There is some dispute about the method of transport involved. Some biologists argue that ocean and air currents are responsible for the transport of plant seeds to Hawaii. Yet the results of flotation experiments and the low temperatures of air currents cast doubt on these hypotheses. More probable is bird transport, either externally, by accidental attachment of the seeds to feathers, or internally, by the swallowing of fruit and subsequent excretion of the seeds. While it is likely that fewer varieties of plant seeds have reached Hawaii externally than internally, more varieties are known to be adapted to external than to internal transport.
The author of the passage is primarily concerned with ______.
选项
A、discussing different approaches biologists have taken to testing theories about the distribution of plants in Hawaii
B、discussing different theories about the transport of plant seeds to Hawaii
C、discussing the extent to which air currents are responsible for the dispersal of plant seeds to Hawaii
D、resolving a dispute about the adaptability of’ plant seeds to bird transport
答案
B
解析
本文作者主要讨论各种有关把植物种子输送到夏威夷的理论。首先,生物学家们认为,由于海洋和气流的缘故,植物的种子被输送到夏威夷;其二,漂浮实验以及气流低温实验结果对有关假设提出质疑;其三,鸟类最有可能把种子带到夏威夷。
转载请注明原文地址:https://www.kaotiyun.com/show/hu1O777K
0
考博英语
相关试题推荐
Eachyear,millionsofpeopleinBangladeshdrinkgroundwaterthathasbeenpollutedbynaturallyhighlevelsofarsenicpoison
Areyoualwayssureyouknowwhatpeoplemeanwhentheytrytodescribetheirfeelingstoyou?Weusebothwordsandgesturesto
Heknewthathewouldbepunishedseverelybecauseofhisseriouserror.Thereforehe______awaythedaybeforeyesterday.
Nanotechnology,accordingtoitsfans,willjump-startanewindustrialrevolutionwithmolecular-sizedstructuresascomplexas
Heplansto______handsurgeryuntilSeptemberinhopesofwinninghisfirstgoldmedalintheBeijingOlympics.
DadCan’tHandleTheseToysAnyparentwithachild【C1】____theagesof3and11cantellyou【C2】____technologyhascreptint
Itwas3:45inthemorningwhenthevotewasfinallytaken.Aftersixmonthsofarguingandafinal16hoursofhotparliamentar
Neverhasastraitjacketseemedsoill-fittingorsoinsecure.TheEuroarea’s"stabilityandgrowthpact"wassupposedtostop
Amidremarkableprogressoninflationandfiscalreform,Italyheadsinto1998withbrightprospectsforeconomicgrowthandits
In1784,fiveyearsbeforehebecamepresidentoftheUnitedStates,GeorgeWashington,52,wasnearlytoothless.Sohehireda
随机试题
“金砖国家”不包括()
李商隐《锦瑟》:__________,蓝田日暖玉生烟。
下列参与形成卫星现象的细胞是
A.上肢对称性皮肤颜色改变B.下肢浅静脉红、肿、硬、有压痛,足背动脉搏动减弱C.趾端坏死,血胆固醇增高D.下肢静脉淤血、水肿、慢性溃疡形成E.下肢变形、粗肿、肢端慢性溃疡形成
A、东北B、甘肃C、福建D、浙江E、云南、广西当归主产于
[2010年,第41题]26号元素的价电子构型为()。
某公司进行一项投资,投资相似项目的投资报酬率为12%,标准离差率为40%,无风险报酬率为4%,并一直保持不变,经测算该项投资的标准离差率为45%,则该项投资的投资报酬率为()。
部分教师平时与学生缺乏交流沟通,不愿花力气研究和掌握学生的思想动态,这反映了这些教师的职业道德存在的问题是()。
已知数列{xn}满足:x0=25,xn=arctanxn-1(n=1,2,3,…),证明{xn}的极限存在,并求其极限.
Forthispart,youareallowedthirtyminutestowriteacompositiononthetopic"MyIdealJob".Youshouldwriteatleast120
最新回复
(
0
)