资料：It’seasytotracetheevolutionoftheautomobile.Atmost，we’reonlytalkingaboutafewcenturiesoftechnologicaldevelopment，andmostoftheplans，prototypesandmodelsarestillaround.Withjustalittleresearch，youcaneasilytracethelatestmodelelectrichybridbacktoitssteam-poweredancestors. Yourfamilytreeisprobablyadifferentmatter.Evenanextensivegenealogychartcanonlyreachbacksofar，andmortalityputsaratherstrictlimitonexactlyhowmany“models”arestillontheroad.Humanity’sevolutionaryprogressionisevenmoredifficult.Westillhaveplentyoflivingprimaterelatives，butmanyofthelifeformsthatconnecttheevolutionarydotsarelongextinct. Evolutionarybiologistsuseseveralmethodstodecipherexactlyhowwecametobeasweare.Infact，thefielditselfencompassesseveraldifferentdisciplinesinadditiontobiology，likegenetics，psychology，geology，archaeologylinguistics，anthropologyandprimatologyjusttonameafew.Naturally，paleoanthropologyalsoplaysakeyrole，aswehavetoturntothefossilrecordformanycluesaboutourancientprimate，humanandnearlyhumanancestors. Whilethefossilrecordbyitsverynatureisincomplete，there’snoshortageoffossilevidencetolinktheplanet’svariedlifeformsintoagreattreeoflife，achartthatscientistscallaphylogenetictree.Youcanthinkofhumansastheverytipofjustonebranchonthattreecalled“hominid.”Chimpanzeesexistattheendofanadjoiningbranchcalled“panin.”Followboththehominidandpaninbranchbackabout5.4millionyears，andyou’llfindapointwherescientiststhinkthetwoconvergedfromasingle，commonancestor. Fossilevidencehelpsscientiststoreconstructthesetrees，butsodomorphologicalandgeneticstudlies.Geneticanalysishasyieldedstrikingsimilaritiesbetweenchimpsandhumans.Assuch，scientistsknowalastcommonancestorofchimpsandhumansexisted，evenifwe’veyettodeterminetheexactspecies.Yetpaleoanthropologistshavefoundnumeroushominidfossilstobridgetheevolutionaryprogressionfromthatunknowncommonancestortomodernhumans.ThesefindsincludesuchfamousEastAfricanfossilsasLucy(Australopithecusafarensis)，whichstrengthenedtheimportanceofbipedalisminhumanevolutionandprovedanessentialmilestoneonourwaytomodernHomosapiens. Fossilevidenceforhumanevolutionwillneverbecomplete，asfossilsthemselvesareraregeologicoccurrences.Nevertheless，byincorporatingotherscientificdisciplines，we’reabletobuildanincreasinglyaccuratepictureofjustwhatourevolutionaryfamilytreeconsistedof. WhatcanbeinferredfromPara.5?
A.Morpholoical and genetic studies helped scientists to trace unknown common ancestor of chimps and humans existed. B.Morphological and genetic studies determined exact species of common ancestor of chimps and humans existed. C.Genetic studies found hominid fossils to bridge the evolutionary progression from unknown common ancestor to modern humans. D.Morphological studies helped finding the famous East African fossils and set up an milestone in this field.正确答案C
