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
34
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 "it" in the passage refers to
选项
A、Protoceratops.
B、Protoceratopsid.
C、Mongolia.
D、version.
答案
A
解析
指代关系题 指示代名词所指代的名词一般出现在指示代名词所属的句子中或者其前面的句子中。本文中指示代名词所属的句子里没有可以替换it的名词,所以要在前面的句子中找。前面的句子是“Protoceratops, a six-foot-long quadrupedal herbivore, is a representative Protoceratopsid.” it指代的是protoceratops还是protoceratopsid呢?一般情况下指示代名词用作主语时,指代其前一句的主语,因此答案是A项。
转载请注明原文地址:https://jikaoti.com/ti/VplYFFFM
0
托福(TOEFL)
相关试题推荐
Studentsoncourseslastingoverayearareusuallygivenuntil______toleavethecountry.
Studentsoncourseslastingoverayearareusuallygivenuntil______toleavethecountry.
Atenancyagreementisa______betweenthetenantandthelandlord.Anassuredshort-holdtenancymeansthatyourlandlordca
Questions9-10AnswerthefollowingquestionsusingNOMORETHANTHREEWORDSforeachanswer.
HowmanypeopleareCindyandBobplanningthepicnicfor?
Completethenotesbelow.UseNOMORETHANTHREEWORDSORANUMBERforeachanswer.INTERNATIONALDRIVINGLICENSESFACTS
"ResearchMethodology"Closescientificmethodbasedonempiricalevidence(=(21))Findaresearchproblemorques
Writethecorrectletter,A-F,nexttoquestions21-26.AVideoResourceCentreBReadingRoomCFoodServiceCentreDPeriodic
Writethecorrectletter,A-F,nexttoquestions21-26.AVideoResourceCentreBReadingRoomCFoodServiceCentreDPeriodic
ENDANGEREDSPECIESAlthoughwecannotdoanythingabouttheplantsandanimalsthatarealready【31】________,wecandosomething
随机试题
上肢的浅静脉是()
男性,28岁。酗酒后突发剧烈上腹绞痛10h伴呕吐、冷汗、面色苍白入院。体检:体温39.1℃,血压11/8kPa,脉搏110次/分,腹上区压痛及反跳痛、腹肌紧张,Grey—Turner征(+)。血清淀粉酶800Somogyi单位。该病人最主要的护理诊断是(
前腭杆的前缘应
心房内部分隔时,卵圆孔位于()。
操作人员要严格遵守计算机的操作程序,并遵循()的要求。
你是城管工作人员,你所在辖区有小商小贩违规占道贩卖烧烤。在整治过程中有一个人说自己失业以此谋生,你怎么办?
联系我国实际,论述法治国家的主要标志。(2013法论35)
中国共产党历史上第一个土地法是()
Thequalityandnumberofacity’spublicroadsofferanexcellentmeansofgaugingitsprosperity.
A、Hecamebackthenextweekend.B、Ittook15hourstodrivealltogether.C、HespentagoodnightinMexico.D、Theyhadtoeat
最新回复
(
0
)