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
自考
Rare Fossil Record The preservation of embryos and juveniles is a rare occurrence in the fossil record. The tiny, delicate s
Rare Fossil Record The preservation of embryos and juveniles is a rare occurrence in the fossil record. The tiny, delicate s
admin
2017-04-24
69
问题
Rare Fossil Record
The preservation of embryos and juveniles is a rare occurrence in the fossil record. The tiny, delicate skeletons are usually scattered by scavengers (食腐动物)weathering before they can be fossilized. Ichthyosaurs (鱼龙) had a higher chance of being preserved than did terrestrial creatures because , as marine animals, they tended to live in environments less subject to erosion. Still, their fossilization required a suite of factors: a slow rate of decay of soft tissues, little scavenging by other animals, a lack of swift currents and waves to jumble and carry away small bones, and fairly rapid burial. Given these factors, some areas have become a treasury of well-preserved ichthyosaur fossils.
The deposits at Holzmaden, Germany, present an interesting case for analysis. The ichthyosaur remains are found in black, bituminous marine shales (页岩) deposited about 190 million years ago. Over the years, thousands of specimens of marine reptiles, fish and invertebrates have been recovered from these rocks. The quality of preservation is outstanding, but what is even more impressive is the number of ichthyosaur fossils containing preserved embryos.
Ichthyosaurs with embryos have been reported from 6 different levels of the shale in a small area around Holzmaden, suggesting that a specific site was used by large numbers of ichthyosaurs repeatedly over time. The embryos are quite advanced in their physical development; their paddles, for example, are already well formed. One specimen is even preserved in the birth canal. In addition, the shale contains the remains of many newborns that are between 20 and 30 inches long.
Why are there so many pregnant females and young at Holzmaden when they are so rare elsewhere? The quality of preservation is almost unmatched and quarry operations have been carried out carefully with an awareness of the value of the fossils. But these factors do not account for the interesting question of how there came to be such a concentration of pregnant ichthyosaurs in a particular place very close to their time of giving birth.
Which of the following best expresses the relationship between the first and second paragraphs?
选项
A、The first paragraph describes a place while the second paragraph describes a field of study.
B、The first paragraph defines the terms that are used in the second paragraph.
C、The second paragraph describes a specific instance of the general topic discussed in the first paragraph.
D、The second paragraph presents information that contrasts with the information given in the first paragraph.
答案
C
解析
推理判断题。第二段是第一段讲述内容的一个例证,因此C正确。
转载请注明原文地址:https://www.kaotiyun.com/show/1m8R777K
本试题收录于:
英语(二)题库公共课分类
0
英语(二)
公共课
相关试题推荐
垄断资本主义国家向外输出资本的财力基础是其存在__________。新殖民主义相比老殖民主义在对外经济侵略上最主要的不同做法是__________。
Weallknowthathumansaredamagingtheenvironment,butwhatcanwedoaboutit?Somepeoplearetryingtodotheirbittobemo
Anunderstandingofman’seffectonthebalanceofnatureiscrucial(关键的)tobeingabletofindtheappropriateremedialaction.
Teachers______theirstudentstobeusefultosocietyinthefuture.
Althoughmanagerscannotpredictthefuture,manyoftheirdecisionsrequirethatthey______(consider)possiblefutureevents.
RareFossilRecordThepreservationofembryosandjuvenilesisarareoccurrenceinthefossilrecord.Thetiny,delicates
RareFossilRecordThepreservationofembryosandjuvenilesisarareoccurrenceinthefossilrecord.Thetiny,delicates
RareFossilRecordThepreservationofembryosandjuvenilesisarareoccurrenceinthefossilrecord.Thetiny,delicates
RareFossilRecordThepreservationofembryosandjuvenilesisarareoccurrenceinthefossilrecord.Thetiny,delicates
随机试题
油田全面开发进入稳定生产后,当含水率达到一定的数值时,油田累积产油量与累积产水量的对数呈()关系。
肾功能检查时尿液中的指标不包括下列哪项
脘腹胀满,不思饮食,呕吐恶心,嗳气吞酸,肢体沉重,怠惰嗜卧,常多自利,舌苔白腻而厚,脉缓。方剂选用
区域火灾风险的评估原则有()。
借贷记账法记账符号“借”表示()。
根据社会保险法律制度的规定,下列关于社会保险费缴纳的表述中,正确的有()。(2016年)
甲公司发生了以下几笔业务:(1)2005年2月,在股票市场上,转让A公司的股票100000股,卖出价格为16元/股,该笔股票的购入价格为12元/股。(2)2005年10月,在外汇市场上,转让100000美元,转让价为100美元兑827元
众所周知,微波辐射具有某种杀伤力。早在20世纪上半叶,研究人员就发现雷达发射的微波达到某种频率后,会使近处的人感到皮肤发热。使用这种微波能量可制造非致命性武器。但怎样的微波既使人感到疼痛,又不造成伤害,这是研究人员面临的主要问题。而这一问题在研制其他微波装
Youngpeoplealwayssufferinrecessions.Employersstop【C1】______thembecausetheyareeasiertosack.Butin【C2】______episodes
Inthe1960s,medicalresearchersThomasHolmesandRichardRahedevelopedachecklistofstressfulevents.Theyappreciatedthe
最新回复
(
0
)