英语阅读题Intheevolutionofmammalsfromreptiles(爬行动物),therewasasuccessionofphysicalchanges:thedevelopmentofwarmblood,bodyhairinsteadofscales,andthebeginningofthenursingoftheyoung.Thisradicalphysicaltrans
英语阅读题
Intheevolutionofmammalsfromreptiles(爬行动物),therewasasuccessionofphysicalchanges:thedevelopmentofwarmblood,bodyhairinsteadofscales,andthebeginningofthenursingoftheyoung.Thisradicalphysicaltransformationprovidedmammalswithagreatertoleranceforexternaltemperatureandrequiredrelianceonspecializedfoodtypes.Whenthedominantdinosaurs(恐龙)becameextinct,theAgeofMammalsbegan.Fortherest60millionyearsmammalsexpandedintothebiologicalvacuumwhichtheywerebetterequippedtoexploitthanallbutafewvarietiesofreptiles.
Thehabitatoflifeformsonearthhasbeentheentireplanet,convenientlydividingtheworldintothebirdsoftheair,thefishofthesea,andthecreaturesoftheland.Theevolutionaryprocessalsocreatedsea-dwellingmammalswhoappearedtoreversetheprocessofevolutionastheyreturnedtothesea.Thewhales’limbsbecameflipperlike,andtheylostthehairontheirbodies,suitingthembettertoaquaticlife.
Ontheotherhand,inthecourseoftheevolutionofbirdsfromreptiles,therewasasuccessionofchangesinthebone,muscle,andskinstructuresoftheanimals.Thiswholesalerestructuringofsomereptilesoveraperiodofthousandsofyearsequippedthenewanimalstoescapetheirpredatorsandtofindfoodmoreeasily.Buttheevolutionaryprocessdidnotstopthere.Onceadaptedtoflight,somebirdscontinuedtochangeandtheprocessseemedtoreverseitself.Aspenguins(企鹅)adaptedtomarinelife,theirwingschangedtoflippersandtheirfeatherstoawaterproofcovering,thussuitingthebirdsforasemi-aquaticexistence.
1.TheAgeofMammalsbeganwhen____
A.animalsevolvedfromreptiles
B.animalsnursedtheyoung
C.animalsweremoretoleranttoexternaltemperature
D.thedominantdinosaursdiedout
2.Itcanbeconcludedfromthispassagethattheancestorsofwhales____
A.werefishB.chasedreptiles
C.livedonthelandD.hadtoomanyoffspring
3Inparagraph2,theword‘aquatic’isclosestinmeaningto____
A.ofearthB.ofland
C.ofriverD.ofwater
4.Certainreptilesgraduallybecameabletoescapequicklyby____.
A.acquiringnewstru