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
Ceratopsia Ceratopsia thrived in North America and Asia during the Cretaceous Period (about 146 to 65.5 million years ago).
Ceratopsia Ceratopsia thrived in North America and Asia during the Cretaceous Period (about 146 to 65.5 million years ago).
admin
2013-04-25
36
问题
Ceratopsia
Ceratopsia thrived in North America and Asia during the Cretaceous Period (about 146 to 65.5 million years ago). Their name means "horned face" and indeed many of them did feature bony horns projecting from their skulls.
(A) The horns may look quite predatory, but Ceratopsians were
herbivores
1, so their horns were defensive in nature and may have been used to enforce order in the group.
(B) Not all Ceratopsians had horns, but all had beaklike mouths.
(C) The fossil record has revealed three distinct families among Ceratopsia: Psittacosaurids, Protoceratopsids, and Ceratopsids. Triceratops, a member of the Ceratopsid family, is probably the best known species of Ceratopsia. With its facial horns and neck display, it exhibits many of the features commonly associated with this dinosaur group.
(D) However, there are species of Ceratopsia that are quite different from the familiar Triceratops.
The Psittacosaurids comprise the Psittacosaurus
genus
2 and the Hongshanosaurus genus. Although not much fossil data are available for Hongshanosaurus, comparisons with Psittacosaurus can be made. Evidence indicates that both were roughly deer-sized bipeds dwelling in East Asia. Hongshanosaurus had beak points on both upper and lower jaws, while only the upper jaw of Psittacosaurus was pointed. Much more fossil evidence is available for Psittacosaurus species. At least one species had long quills along its back and tail. Researchers speculate these quills were used for display during mating or fighting. As early Ceratopsians, the Psittacosaurids had many anatomical features that would show up in similar or interestingly modified forms in later species, but none of the Psittacosaurids had the neck frills or facial horns that came to be associated with the Ceratopsians.
Although their name suggests that the Protoceratopsids were the first of this dinosaur group to have horned faces, they, in fact, lacked the well-developed horns of later species. While they more closely resembled the Ceratopsids on the whole, they were still relatively small and hornless. Protoceratops, a six-foot-long quadrupedal herbivore, is a representative Protoceratopsid. Fossil examples found in China and Mongolia show that it had a turtle-like beak and a neck frill, a version of which would show up among the more familiar Ceratopsids. While Protoceratops did have some knobby points on its skull, the points only slightly hinted at the impressive horns that appeared on the Ceratopsids.
With the arrival of Triceratops and other advanced Ceratopsids, Ceratopsia reached new levels of sophistication, variety, and size. All Ceratopsid fossils have been found in western North America and reveal that they were quadrupedal herbivores with beaked jaw tips and rows of teeth specialized for shearing. The family featured a remarkable array of horns, neck frills, and spines. These neck frills, manifesting in various shapes and sizes, probably were too thin to be practical as a defense against predator species, and researchers speculate that they were used during mating displays, for anchoring jaw muscles, for regulating body temperature, or for a combination of these purposes. Most Ceratopsids had two long brow horns and a short horn on the nasal ridge. Because the Ceratopsids were vegetarian and fairly large (up to 30 feet long and 10 feet tall), researchers think that the horns, along with the neck frills, largely served functions of competition, whether in displays or combat. Moreover, since intraspecific conflicts often are tests of strength rather than fights to the death, thin neck frills may have been sturdy enough to provide some protection during such confrontations.
There is evidence of Ceratopsian species that do not neatly fall into the familial categories as described. While these species appear closely related to Ceratopsia, they tend to be smaller and more primitive. Researchers have debated over recognizing a distinctly new Ceratopsian family or grouping these misfit species with an existing family. Psittacosaurids, Protoceratopsids, and Ceratopsids are the commonly accepted Ceratopsian families with established member species and defined characteristics. Despite some controversies over minor species, a view of the Ceratopsian families is a view of fascinating adaptations and development in a unique dinosaur group.
The word "comprise" in the passage is closest in meaning to
选项
A、include.
B、belong in.
C、result from.
D、assimilat
答案
A
解析
词汇题 comprise的意思是“包括;由……构成”,因此,include的意思与其最接近。
转载请注明原文地址:https://kaotiyun.com/show/0YyO777K
0
托福(TOEFL)
相关试题推荐
WhichpiechartshowstheagesoftheAsianstudentssurveyed?WhichbarchartshowsthepercentageofAsianstudentswhomade
SECTION1Questions1-10Questions1-5CompletefollowinginformationusingNOMORETHANTHREEWORDSORNUMBERSforeachanswe
WhatisthetitleoftheseriesofpresentationsthatDavidPricewillmake?WhatitemhasDavidPricegiveneachstudent?
TheprofessoralreadyknowssomethingaboutClarefromher______.
TheprofessoralreadyknowssomethingaboutClarefromher______.
Completethefollowinginformation.
"ResearchMethodology"Closescientificmethodbasedonempiricalevidence(=(21))Findaresearchproblemorques
WriteNOMORETHANTWOWORDSforeachanswer.BeWellOnlineProgramme=interactivewebsitewithresourcestohelpreach
Completethenotesbelow.WriteONEWORDONLYforeachanswer.HydropowerRenewable—constantsource(31)fromnatural
Completethetablebelow.WriteAiftherepairwillbedoneimmediately.Biftherepairwillbedoneduringthefollowingweek
随机试题
给定程序MODll.C中函数fun的功能是:统计substr所指子字符串在str所指字符串中出现的次数。例如,若字符串为aaaslkaaas,子字符串为as,则应输出2。请改正程序中的错误,使它能计算出正确的结果。注意:不要改动main函数,不得增
小李在推销某饮料时说:这种饮料含有一些人体必需的营养成分,所以不喝这种饮料就会缺乏这些必需的营养。以下哪项最能削弱小李的推销?
我国公务员录用的资格条件。
《李将军列传》一文中,交代李广被迫自杀的战争是“随卫青击匈奴之战”。()
注射剂中,吐温-80常用作
A.快速充盈期B.等容舒张期C.缓慢射血期D.快速射血期E.等容收缩期容积快速增大为()
善于清心胃实火而除烦.止呕的药物是
营销部王华的病假天数修改为2天,请重新计算“销售人员”工资表数据。
该校教师最多的是哪一年?( )哪一年中年男教师的增长幅度最大?( )
为真诚答谢【155】大英语学习者对本社【156】版的词典的厚爱,本社在暑期【157】展“打好英语学习基本功,英文词典伴您行”活动,凡在活动期【158】购买我社精品词典——《当代高级英语辞典》、《英汉多功能词典》的【159】者,均可获赠方便实用的环【160】
最新回复
(
0
)