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
Sexual Reproduction Birds do it. Bees do it. But dandelions don’t. The prodigious spread of these winsome weeds underscores a
Sexual Reproduction Birds do it. Bees do it. But dandelions don’t. The prodigious spread of these winsome weeds underscores a
admin
2018-06-29
19
问题
Sexual Reproduction
Birds do it. Bees do it. But dandelions don’t. The prodigious spread of these winsome weeds
underscores a little-appreciated biological fact
. Contrary to human experience, sex is not essential to reproduction. Asexual organisms can often churn out multiple generations of clones, gaining a distinct edge in the evolutionary numbers game. And therein lies the puzzle: If sex is such an inefficient way to reproduce, why is it so widespread?
Sex almost certainly originated nearly 3. 5 billion years ago as a mechanism for repairing the DNA of bacteria. Because ancient earth was such a violent place, the genes of these unicellular organisms would have been frequently damaged by intense heat and ultraviolet radiation. " Conjugation" — the intricate process in which one bacterium infuses genetic material into another — provided an ingenious, if cumbersome, solution to this problem, although bacteria continued to rely on asexual reproduction to increase their numbers.
Animal sex, however, is a more recent invention. Biologist Lynn Margulis of the University of Massachusetts at Amherst believes the evolutionary roots of egg and sperm cells can be traced back to a group of organisms known as rotests that first appeared some 1. 5 billion years ago.(Modern examples include protozoa, giant kelp and malaria parasite. ) During periods of starvation, Margulis conjectures, one rotest was driven to devour another. Sometimes this cannibalistic meal was incompletely digested, and the nuclei of prey and predator fused. By joining forces, the fused cells were better able to survive adversity, and because they survived, their penchant for union was passed on to their distant descendants.
From this vantage point, human sexuality seems little more than a wondrous accident, born of a kind of original sin among protozoa. Most population biologists, however, believe sex was maintained over evolutionary time because it somehow enhanced survival. The mixing and matching of parental genes, they argue, provide organisms with a novel mechanism for generating genetically different offspring, thereby increasing the odds that their progeny could exploit new niches in a changing environment and, by virtue of their diversity, have a better chance of surviving the assaults of bacteria and other tiny germs that rapidly evolve tricks for eluding their hosts’ defenses.
The word "underscore" underlined in Paragraph 1 most probably means______.
选项
A、overestimate
B、underestimate
C、underline
D、underlie
答案
C
解析
词义题型,答案是C。underscore此处意为“强调、凸显”,A选项意为“高估”,B选项意为“低估”,C选项意为“强调”,D选项意为“构成……的基础或原因”,故选C。本题核心:1.充分利用上下文语境推测词义;2.区分单词之间的细微差异。本题中underscore、underline、underlie前缀相同,对三者表意异同的甄别要依赖于平时对常见常用词汇的积累。
转载请注明原文地址:https://kaotiyun.com/show/vTMO777K
本试题收录于:
CATTI二级笔译综合能力题库翻译专业资格(CATTI)分类
0
CATTI二级笔译综合能力
翻译专业资格(CATTI)
相关试题推荐
Whichofthefollowingcanbestdescribehissituation?
AdelegationofAmericanofficialsappearedbeforeaninternationallegalpanelon(36)toarguethatinitsfight(37),theUn
Whatisthecommonopinionaboutageandwork?
WhendidIbeginmygenealogyresearch?
A、In1957.B、In1956.C、In1925.D、In1706.B数字信息的找寻和判断。根据原文OnthefoggynightofJuly25,1956,oneofthegreatseadisastersof
A、正确B、错误A推理判断题。根据原文Politicallythewaterwaysystemunitedthenationinawayfewhadimaginedpossible,bythemid-1800s,faste
Thepossiblementalhealtheffectsofcitylivingaffectmanypeople.Peopleoftenmovetocitiesforbetterjobsandmorecultu
Theterm"leader"hasbeenusedalmosttothepointof【C1】______,nowbrandinganyonewho【C2】______inaleadershiprole.Butthe
Asagambler,IhavealwaysbeenattractedtoLasVegas.AndIthoughtthecitywastheperfectplacetotakethebiggestgamble
Healwaysincludedsomethingabovetheunderstandingofhishearersinordertopreventthemfrombecoming______andtostimulate
随机试题
Tounderstandthemarketingconcept,itisonlynecessarytounderstandthedifferencebetweenmarketingandselling.Nottooma
视网膜中感光最敏锐的部位是()
A、大叶性密度均匀磨玻璃状阴影,逐渐溶解呈虫蚀样空洞B、小片状或斑点状阴影,可融合和形成空洞C、纤维厚壁空洞、肺门抬高和肺纹理呈垂柳样D、空洞形态不一,可呈多个空腔的虫蚀样空洞E、向外、向上的弧形影浸润性结核病X
宽度量测方法和要求为,在实地线状地物()处量测宽度,精确到0.1m,并在调查底图对应实地位置打点标记量测点及其宽度值。
2012年张某将其一项专利权转让给A国一家企业,取得转让收入120000元,按A国税法缴纳了个人所得税15000元;同年在A国提供劳务,取得劳务报酬200000元,按A国税法缴纳了个人所得税5.5000元。2012年张某应就来源于A国所得在国内缴纳个人所得
(2015·江苏)小学生在英语课堂上学习“书”的英语单词“BOOK”,按照奥苏贝尔的学习分类,这里的学习属于()
某班有战士7人,每两人一组,轮流放哨,每2个小时换班一次,某两人第一次一同放哨开始,到下次这两人再一同放哨,最长需要()个小时。
简述教育的显性功能和隐性功能的区别。
理想是人们对美好未来的向往和追求,是人们奋斗的目标和精神支柱,也是激励人们发奋向上、不断进取的强大动力,是个人和民族的灵魂所系。对理想的认识正确的是()
A——SafetyhammerJ——HandleofemergencybrakeB——Hittingp
最新回复
(
0
)