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如图，足够长的平行光滑金属导轨水平放置，一端连接一电阻，导轨所在的空间存在竖直向下的磁场（图中未画出），导体棒MN放在导轨上，与导轨接触良好．导轨和导体棒的电阻均可忽略不计，在平行于导轨的恒定拉力F...
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高三下学期物理《》真题及答案
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如图所示水平放置的光滑平行金属导轨间距为L.导轨上有一质量为m电阻为r的金属棒ab导轨的另一端连接电
随着ab运动速度的增大，其加速度将减小
外力F.对ab做的功等于电路中产生的电能
棒克服安培力做的功一定等于电路中产生的内能
当ab棒的速度为v时，ab两端的电势差为BLv
如图甲所示两根足够长的平行光滑金属导轨固定放置在水平面上间距L.＝0.2m一端通过导线与阻值为R.=
如图在一磁感应强度B.=0.5T的匀强磁场中垂直于磁场方向水平放置着两根平行金属导轨导轨的电阻不计.
两根平行光滑金属导轨MN和PQ水平放置其间距为0.60m磁感应强度为0.50T的匀强磁场垂直轨道平面
如图13所示两根水平放置的相互平行的金属导轨abcd表面光滑处在竖直向上的匀强磁场中金属棒PQ垂直于
在棒PQ右侧垂直于导轨再放上一根同样的金属棒
在棒PQ棒右侧垂直于导轨再放上一根质量和电阻均比棒PQ大的金属棒
将导轨的a、c两端用导线连接起来
将导轨的a、c两端和b、d两端分别用导线连接起来
.如图所示相距为L.的足够长光滑平行金属导轨水平放置处于磁感应强度为B.方向竖直向上的匀强磁场中导轨
如图在一磁感应强度B.=0.5T的匀强磁场中垂直于磁场方向水平放置着两根平行金属导轨导轨的电阻不计.
如图甲所示两根足够长的平行光滑金属导轨固定放置在水平面上间距L.＝0.2m一端通过导线与阻值为R.=
如图13所示两根水平放置的相互平行的金属导轨abcd表面光滑处在竖直向上的匀强磁场中金属棒PQ垂直于
在棒PQ右侧垂直于导轨再放上一根同样的金属棒
将导轨的a、c两端用导线连接起来
将导轨的a、c两端和b、d两端分别用导线连接起来
在棒PQ棒右侧垂直于导轨再放上一根质量和电阻均比棒PQ大的金属棒
如图8所示水平放置的平行金属导轨相距为d导轨一端与电源相连垂直于导轨平面的匀强磁场的磁感应强度为B方
如图所示间距为L.的光滑平行金属导轨水平放置导轨上有一电阻为r的金属棒ab与导轨接触良好导轨一端连接
金属棒a端电势比b端高
电阻R.两端的电压为BLv
ab棒受到的安培力的方向向左
外力F.做的功等于电阻R.上发出的焦耳热
如图所示两根平行光滑金属导轨PQ和MN间距为d它们与水平面间的夹角为α上端与阻值为R的电阻连接导轨上
如图所示efgh为水平放置的足够长的平行光滑导轨导轨间距为L.=1m导轨左端连接一个R.=2Ω的电阻
相距为L的足够长光滑平行金属导轨水平放置处于磁感应强度为B方向竖直向上的匀强磁场中导轨一端连接一阻值
如图所示在方向竖直向上的磁感应强度为B.特斯拉的匀强磁场中有两条光滑固定的平行金属导轨MNPQ导轨足
10分两根平行光滑金属导轨MN和PQ水平放置其间距为d=0.6m磁感应强度为B.=0.5T的匀强磁场
如图所示足够长的平行光滑金属导轨水平放置宽度L.=0.4m一端连接R.=1Ω的电阻导轨所在空间存在竖
如图所示足够长的平行光滑金属导轨水平放置宽度L=0.4m一端连接R=1Ω的电阻导轨所在的空间存在竖直
如图所示在方向竖直向上的磁感应强度为B的匀强磁场中有两条光滑固定的平行金属导轨MNPQ导轨足够长间距
如图18所示efgh为水平放置的足够长的平行光滑导轨导轨间距为L.=1m导轨左端连接一个R.=2Ω的
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某同学为探究不同物质及浓度对洋葱表皮细胞失水的影响设计了如下实验．请回答 步骤1配制具有一定浓度梯度的蔗糖和氯化钠溶液各10mL分别加入培养皿中加盖编号． 步骤2从同一紫色洋葱鳞片叶的相同部位撕取外表皮若干迅速分别投入到上述培养皿中使其完全浸入溶液浸泡10min． 步骤3依次取出洋葱鳞片叶外表皮制成临时装片用显微镜观察并拍照． 步骤4统计照片中细胞总数及质壁分离细胞数计算质壁分离细胞占比结果如图． 1步骤1中培养皿加盖的目的是．步骤3中制作临时装片时需在载玻片中央滴加1～2滴． 2实验表明当两种溶液的浓度低于0.2mol•L﹣1时洋葱表皮细胞几乎不发生质壁分离原因是．在0.4mol•L﹣1蔗糖溶液中大约只有20%的细胞发生了质壁分离同一表皮的细胞质壁分离不同步的原因是． 3根据实验结果分析0.6mol•L﹣1NaCl溶液的渗透压比0.6mol•L﹣1蔗糖溶液的渗透压． 4在“观察植物细胞质壁分离及复原实验”中一般认为使材料中50%左右的细胞发生质壁分离的溶液浓度为理想实验浓度因为用该浓度溶液进行实验不宜选用0.35mol•L﹣1NaCl溶液进行实验的理由是．
Thechoirrehearsal合唱排练oftheschoolyeartookplaceintheschoolhall.Allthestudents1 togethertosing.Iwatchedasmyeldersisterandhergradetooktheirplacesonthe2MeanwhileIcouldhearsomestudentslaughingand3atagirlnexttomysister.I'dneverseenthisgirlbefore.Agirl4inmyearDoyouknowshe's5diapers纸尿裤? AfterschoolthateveningIaskedmysisteraboutthegirlthatIsaw.ShetoldmehernamewasTheresaandthatshewasanicegirl.Whywerethosekidsbeing6toher?Iasked.Becausethey're7shesaid. OnedayIwaswalkinghomefromschoolwhenIheardvoicesbehindmeThere'sthelittleidiot's白痴的youngsister.Doesyoursisterwether8too?Iwalkedfasterandthenfeltastone9meintheback.WhenIgothomeIpushedmywayintoherroom10atherWhydoyouhavetobethatgirl's11?Idon'tseeanyoneelsebeing12toher.JanelleyelledbackBecauseshe'sawonderfulpersonandshe's13!Iwillrememberthosewords14Ilive.Theresawettedhertrousersbecauseshehadan15whichwaskillingher.Mysistertheonlyoneniceenoughtobeherfriendandstickupforher.Severalmonths16Theresa17. Ifelt18thatJanellewasmysister.Throughouttheyearsshealwaysmadefriendswitheveryone.Itdidn'tmatterwhethertheywerebrilliantornot?Sheneverleftanyonefeeling19.Itwasshewho20meandtaughtmenevertolookatanyoneinthesamewayagain. 1A.pulled B.joined C.lived D.crowded 2A.stand B.room C.stage D.bench 3A.pointing B.glaring C.aiming D.glancing 4A.threw B.yelled C.shouted D.whispered 5A.wearing B.dressing C.putting D.carrying 6A.kind B.friendly C.rude D.merciful 7A.interesting B.polite C.generous D.stupid 8A.trousers B.shoes C.socks D.coat 9A.beat B.hit C.blocked D.touched 10A.glaring B.screaming C.staring D.talking 11A.friend B.classmate C.singer D.teacher 12A.tough B.nice C.terrible D.cruel 13A.arriving B.approaching C.dying D.recovering 14A.atthesametime B.themoment C.aslongas D.assoonas 15A.problem B.dream C.kindness D.illness 16A.ago B.before C.away D.later 17A.diedout B.becamewell C.fadedout D.passedaway 18A.disappointed B.shamed C.proud D.ashamed 19A.wise B.alone C.awesome D.fearful 20A.changed B.scared C.developed D.improved
把下列数据用科学记数法表示出来:人的大脑约有10000000000个细胞
酵母菌是常用的生物实验材料相关叙述正确的是
下列关于DNA重组技术基本工具的叙述正确的是
科研人员调查某地不同植物花冠筒的深度与昆虫口器长度之间的关系结果如图．相关叙述错误的是
Keepingadiaryisoneoftheuseful1waytoimproveourEnglishability. 2comparewithotherformsofwritingitisshorterandtakes3littletime.ItcanhelpustodevelopthehabitofthinkinginEnglish.Ifwepersistinthispracticegraduallywe'lllearnhowtoexpress4weinEnglish.WekeepadiaryinEnglish5canhelpusdealwithmanydifficulties.Inthefirstplaceitoftenhappensthatwehavetrouble6findproperwordsandphrasestogiveexpressionstoourmind.SecondlytherearemanyidiomaticwaysofsayingthingsinChinese.Andit's7extremehardforustoputthemintoEnglishproperly. ManyyearsagomyEnglishteachercameupwithasuggestionthateverystudent8haveanotebookandaChinese﹣Englishdictionarywithineasyreach.Wheneversomethingbeatsuswecanfirstputitdowninournotebookandthenconsultourdictionary.WecanalsoaskourEnglishteacherforhelpifnecessary.InshortIbelievethatitis9greatusetokeepadiaryinEnglishfor10developmentofourwritingskills.
利用科学记数法表示的数原来各是什么数7.04×106=
人参皂甙具有抗肿瘤等作用．科研人员设计如图1所示流程制备人参皂甙Rg3并研究了过程③生物反应器中人参细胞产量人参皂甙Rg3产量随培养时间的变化结果如图2．请回答 1过程②通常需用酶处理将愈伤组织分散成单个细胞．过程③通常采用振荡培养除有利于增加溶解氧外还能防止． 2由图2可知生物反应器中人参细胞的数量呈增长影响人参皂甙Rg3产量的因素有和． 3科研人员研究了人参皂甙Rg3LeY单克隆抗体LeY是一种肿瘤相关抗原以及两者联合使用联合组对人子宫内膜移行上皮癌细胞数量增长的影响结果如图3． ①药物抑制癌细胞数量增长的途径可能有等． ②计算细胞数量增长抑制率需测定空白对照组培养相同时间后的细胞数．写出计算细胞数量增长抑制率的公式． ③根据图3结果可得出的结论是．
以洋葱为材料进行DNA的粗提取与鉴定实验相关叙述错误的是
如图是人体特异性免疫反应的部分过程示意图相关叙述错误的是
ThesuiciderateinAmericaisupby18%since2000.Thisisnotmerelyatragedy;itmatterspoliticallytoo.Theriseislargelyamongwhitemiddle﹣agedpoorlyeducatedmeninareasthatwereleftbehindbyboomsandcrushedbybusts.Theirdeathsareasymptomoftroublesthatshouldnotbeignored. NonethelessbeyondAmerica'sgloomytrendisamoreoptimisticstory:thatatagloballevelsuicideisdownby29%since2000.Asaresult2.8mliveshavebeensavedinthattime﹣threetimesasmanyashavebeenkilledinbattle.Thereisnoonereason.Itishappeningatdifferentratesamongdifferentgroupsindifferentplaces. Whyarepeoplenowlesslikelytotaketheirownlives?Urbanizationandgreaterfreedomhavehelped.AccountsofthosewhoattemptsuicideandoftherelativesofthosewhosucceedsuggestthatmanyyoungAsianwomenweredriventodespairbyviolenthusbandsandoverbearingin﹣laws.Aspeoplemovetocitiesandthegripoftraditionloosenswomenhavemorechoiceaboutwhomtheymarryorlivewithmakinglifemorebearable.Leavingthevillagehelpsinanotherwaytoo.Becausefarminginvolveskillingthingsruralfolkarelikeliertohavethemeanstokillthemselves﹣gunspesticides﹣tohand. Effortstocontrolaccesstothemeanstokilloneselfcanhelptoo.Suicideissurprisinglyimpulsive.AstudyofyoungChinesewomenwhohadtriedtokillthemselvesshowedthatthree﹣fifthshadbeencontemplatingsuicideforlessthantwohoursandoneintenforlessthanaminute.Of515peoplewhohadsurvivedtheleapfromSanFrancisco'sGoldenGateBridgebetween1937and197194%werestillalivein1978﹣whichsuggeststhatasuicidepostponedislikelytobeasuicideprevented. 1Whichisnotthereasonofsuicidedecreasing? A.Morefreedom B.Moreforcedmarriages C.Urbanization D.Morecontrolonmeans 2Wecaninferfromparagraph4that A.manypeopledecidedtokillthemselvesafteraseriousconsideration B.about484peoplestillalivein1978aftersurvivingtheleapbetween1937and1971 C.515peopletriedtosuicidebyjumpingfromGoldenGateBridgebetween1937and1971 D.three﹣fifthsyoungChinesewomenmaydecidetosuicidewithin2hours 3Whatshouldbethebesttitleforthetext? A.Moreliveshavebeensaved B.Suicideissurprisinglyimpulsive C.Asuicidepostponedisasuicideprevented D.Whysuicideisfallingaroundtheworld
TampaBayhasalongandcolorfulhistorywhichislocatedonthewestofFlorida.Andthereareplentyofeventsonholidayseveryyear.ThefollowingarethetopthingstoexperienceinTampaBayoverChristmas. JackieEvancho ThesuperstarexplodedontothenationalsceneafterherfirstperformanceonNBC'sAmerica'sGotTalentwhichleftaudiencesandjudgesatthetalkshowastonishedthatsuchavoicecouldcomefroma10﹣year﹣oldgirl.7:30pmRuthEckerdHall102Mullen﹣BoothRoadClearwater.﹩35～﹩65.727756﹣7400. HolidayLightsintheGardens Strollthroughthegardenswithmorethan1milliontwinklylightslasersFlorida﹣styleshowscartooncharactersvisitswithSantaandentertainersliningthepathway.5:30pmFloridaBotanicalGardens1250UlmertonRoad.LargoDonationof﹩4suggested;12andyoungerfree.727582﹣5900. RockapellaChristmas Thefive﹣manpopbandtakesonclassicholidayfavoritesongsandtheirneworiginals.7:00pmCapitolTheater.405ClevelandStClearwater.﹩25～﹩48.727791﹣7400. WordierthanThou ProseandShortStoryOpenMic:Aspecialopenmicseriesfocusingonstorytelling.Poetry诗歌andmusicalperformancesarenotallowed.Theeventincludesaperformancebyafeaturedreaderfollowedbynumerous10﹣minuteopenmicslots.7:00pmStudio@620357FirstAve.St.Petersburg.﹩5.727895﹣6620. HolidayClassicMovieSeries It'sAWonderfulLife:Enjoyselectedholidayclassicswithasing﹣alongofholidaycarolsbytheMightyWurlitzerTheatreOrganbeforeeachshow.7:30pmTampaTheater712FranklinRoadTampa.﹩10﹩8members/children.727274﹣8983. 1WhatcanwelearnaboutJackieEvancho? A.Sheisasuperfilmstar. B.Shebroadcastsnewsat7:30pmeveryday. C.Shehasaspecialtalentforspeech. D.Shebegantospeakwhenshewas10. 2Whichactivityisadmissionfreeforchildren? A.RockapellaChristmas. B.HolidayLightsintheGardens. C.WordierthanThou:ProseandShortStoryOpenMic D.HolidayClassicMovieSeries:AWonderfulLife 3Whereshouldyougoifyouareastorylover? A.Studio@620. B.RuthEckerdHall. C.CapitolTheater. D.FloridaBotanicalGardens.
利用科学记数法表示的数原来各是什么数-5.18×103＝
把下列数据用科学记数法表示出来中国森林面积约为128630000公顷
目前我国广泛种植的甘蓝型油菜AACCAC表示不同染色体组是由白菜AA2n＝20与甘蓝CC2n＝18经种间杂交染色体自然加倍形成的．科研人员利用早熟白菜A′A′2n＝20A′与A中染色体能正常配对与甘蓝型油菜为亲本培育稳定遗传的早熟甘蓝型油菜新品种主要过程如图．请回答 1甘蓝型油菜根尖分生区细胞中含有条染色体．亲代杂交时需要对甘蓝型油菜进行授粉等操作．F1杂种甘蓝型油菜的正常体细胞中含有个染色体组． 2途径1不能获得种子有人提出的解释有①F1不能产生可育的雌雄配子②F1产生的雄配子不育雌配子可育③F1产生的雄配子可育雌配子不育．结合途径2上述分析合理的是填序号． 3减数分裂时联会的染色体能正常分离不能联会的染色体则随机分配．经途径2获得的后代体细胞中染色体数介于之间其中筛选的甘蓝型油菜A′ACC细胞中来源于F1的染色体组是． 4随着生物技术的发展还可用技术培育早熟甘蓝型油菜这种育种技术的主要优点是．
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SirJamesPaulMcCartneyisanEnglishsingersongwritermulti﹣instrumentalistandcomposer作曲家.HegainedworldwidefameasthebassguitaristandsingerfortherockbandtheBeatles.Howeverit'snotjustthewordsandmusicofhissongsthatPaulusestoexpresshisfeelingsaboutthingsthatarereallyimportanttohimbuthehasalsocloselytakenpartingettingtogetheranexcitingbookforchildren. Hehasbeenworkingwithillustrator插画师GeoffDunbarandwriterPhilipArdaghtofindawaytoputwordsandpicturesintoastoryaboutanimalprotection.Theresultisastorywithanimportantmessagecontainedinabeautifulbook.Geoffdreweveryoneofthebook's84illustrationsandPhilipmadePaulandGeoff'sideascometogetherinaveryentertainingwaythatallchildrenwillenjoyreading. ThreeluckyreadersofTheNewspaperTodaywonthechancetointerviewPaulaboutHighintheClouds. OnedayinPaul'sofficeAlexMylesandJessicawastednotimeinaskingPaulGeoffandPhiliphowtheideaforthestorycameabout.Paulexplainedthathehadbeeninterestedinanimalrightsforaslongashecouldremember.SeeingtheWaltDisneyfilmofBambiwhosemotherisshotbyhuntershadabigeffectonhimasachildandmadehimthinkthathuntingwasn'tcool. Paulsaidtheydidn'twanttotellpeoplewhattodointhebook.Theyjustwantedtogetacrosstheimportanceaboutanimalprotection. 1HowdoesPaulexpresshisfeelingapartfromthewordsandmusicofhissongs? A.Bydoingwhathecantoinspirepeople. B.Bywritingabookaboutchildren. C.Byillustratinganexcitingbookaboutanimals. D.Byjoiningingettingtogetherachildren'sbook. 2Whowrotethewordsofthebookaccordingtothesecondparagraph? A.GeoffDunbar B.PhilipArdagh C.PaulMcCartney D.MylesandJessica 3WhatisHighintheClouds? A.OneofPaul'snewsongs. B.TheplacewherePaulworks. C.Abookaboutanimalprotection. D.AnarticleinTheNewspaperToday. 4Whatdoestheunderlinedphrasegetacrossprobablymean? A.make…clear. B.realize. C.ignore. D.payattentionto.
Tocommunicatewithforeignersitisimportanttoknowtheirsocialcustoms1.Oryoumayhurtthefeelingsoftheotherpartywithoutactuallyintendingtodoso.Herearesomegeneraltips. 2don'thesitatetoask.SomeJapaneseseemtofeelthatitisimpolitetoaskbackevenwhentheydon'tquiteunderstand.Howeverit'smuchbettertosaythatyoudon'tunderstandthantopretendyouunderstandandanswerveryunclearly.Whenyoudon'tunderstandyoumaysayI'mafraidIdon'tunderstandyou.Wouldyoumindsayingitagain? •Alwaysanswerwhenyouareaskedaquestion.Westernersconsideritveryrudeifaquestionisnotanswered.Theythinkitisrudetoignoreaquestion3.SomanyJapaneseonlylaughnervouslywithoutsayinganythingwhentheyarespokento.ThiscomesfromembarrassmentbutnothingismoreunpleasantforWesterners. •Speakoutwhatyouthink.Westernersexpresstheiropinionsfreely4.Theydon'tmindhearingviewsthatdifferfromtheirown.Youmayexpressfranklywhatyouthinkorfeelofcoursebutyoumustn'tberudeinyourmannerofspeech. 5.TheEnglishuseofYesandNoisthesameasinJapaneseinaffirmative肯定的questionsbutinnegativequestionstheuseisopposite.InordinaryEnglishconversationsitisusualtoaddsomethingafterthemlikeYesbyallmeans.NoIreallydon't.MayIseeit? A.Don'tanswertoosimply B.Ifyoudon't'understand C.ItisthesamewiththeJapanese D.Besuretogiveyourdifferentopinions E.ItissurprisingtofindJapanesearedifferent F.Thisisespeciallytruewhencarryingonaconversation G.Theyfeelitisnaturalforpeopletohavedifferentideas
XiaoLiacollegestudentbornafter1995usedtowashherhaireverytwodays.Butastheweatherhasgotcoldershehasbecomelazier.Shehasboughtamistspray喷雾器whichallowshertowashherhairlessoften.IwouldalsoliketohaveaproductthatcouldsavemethetroubleofputtingonmakeupshetoldOrientTodayapublicationaffiliatedtoHenanTelevision. SheisnottheonlyyoungChinesewhospendsmoneybecausesheslazy.AccordingtoareportissuedbyChina'se﹣commerceplatformTaobaoonChina'slazyeconomyChinesepeoplespent16billionyuanonproductsandservicesonlinein2018. Theso﹣calledlazyeconomyreferstoanewtypeofconsumptionofproductsandserviceswhicharedesignedtosavetimeandlabor.Accordingtothereportmanypeopleofthepost﹣1995generationbuyhigh﹣techelectronicdevicessuchasfloormoppingrobotsandautomaticwindowcleanerswhichsavethetroubleofdoinghouseholdchores.Meanwhiletake﹣outfooddeliveryservicesarealsopopularamongpeoplebomafter1995. Youngpeoplearewillingtospendmoneyonsuchproductsbecausetheywanttoenjoyhard﹣earnedleisure休闲timeafterabusyandstressfuldayatworkorschoolreportedGlobalTimes.Becausetheyneedtofocusontheirstudiesorjobstheseso﹣calledlazypeopletendtousetheirleisuretimemoreefficiently. Whilethelazyeconomymightbeconvenientforyoungpeopleitmightalsocreateproblems.The'lazyeconomy'oncampusisexpressedinthingslikepeoplebuyingfoodorotherthingswithoutleavingthedormitory宿舍.AsaresulttheystayintheirdormitoriesalldaylongplayingoncomputersandsmartphonesateachersumamedWenfromBeijingJiaotongUniversitytoldChinaNews. AccordingtoJinanDailythissituationcouldleadtoyoungpeoplebecominglesssociableandevendevelopingproblemsofcommunicatingwithothers.Youngpeopleshouldbecautiousaboutit. The'lazyeconomy'isachoiceoflifestyle.WhilethelazyeconomysavestimeandlaborthesavedtimeshouldbeusedtodovaluablethingscommentedOrientToday. 1XiaoLiismentionedto. A.introducealazygirltoreader B.explainhowyounggirlslivenowadays C.leadtothetopicofthetext D.tellusthegenerationbecomemoreandmorelazy 2What'slazyeconomy? A.Anewtypeofconsumptioncreatedbypost﹣1995generation. B.Apatternofconsumptioninwhichpeoplesavetimeandlabor. C.Anewtypeofsocietyinwhichpeoplebecomemoreandmorelazy. D.Apatternofconsumptionisdesignforthepost﹣1995generation. 3Whyyoungpeoplelikeonlineshoppingaccordingtothepassage? A.Becausethegoodsonlinearecheaper. B.Becausetherearevarietiesofgoodsonline. C.Becauseyoungpeoplewanttomakethebestofleisure休闲time. D.Becauseyoungpeoplearelazier. 4Whichisthedisadvantageoflazyeconomyaccordingtothepassage? A.Makingyoungpeoplelazy. B.Buyingunhealthyfoodonline. C.Wastingmoney. D.Makingyoungpeoplelesssociable.
如图为某植物2n＝24基因型为AaBb两对基因位于两对同源染色体上减数分裂过程中不同时期的细胞图象相关叙述正确的是
Batsaretheonlymammalsthatcanflyagreatdistancebuttheyhaveanotherability.Manybatsliveaverylongtimeforananimaltheirsize. Europeanresearchersarestudyingbatstounderstandwhytheylivesolong.Theyhopetomakediscoveriesaimedatfightingtheagingprocessinhumanbeings.Lastweekthegroupofscientistssaidtheyhadidentifiedimportantbiologicalqualitiesinsomebatspecies. Thegroupstudiedbatchromosomes染色体alineofgenesfoundinthenucleusofcells.Thescientistsweremostinterestedinstructuresconnectedtotheendsofthechromosomes.Theyarecalledtelomeres.Telomeresprotecttheendsofchromosomeswhichshorteneachtimeacelldivides.Scientistsbelievethisshorteningprocesscausescellstobreakdown.Theysaythisiswhatcausesaging. TheEuropeanresearchersstudied493batsfromfourbatspecies.Thegroupusedinformationthathadbeengatheredovermorethan60years.Oftheseanimalsthegreatermouse﹣earedbatgenerallylivedthelongestanaverageof37years.ThescientistssaidthisandarelatedspecieswhicharegroupedtogetherunderthenameMyotishadtelomeresthatdidnotshortenwithage. Thescientists'findingssuggestthatthesebats'cellshavetheabilitytomaintainandrepairtheirtelomeres.Thistheysaidhelpsguardagainsttheagingprocess. Basedonitsbodysizeabatlikethegreatermouse﹣earedbatwouldbeexpectedtolivefouryears.Butthesemammalshavebeenfoundtolivenearly10timeslongerthanthat. 1Whichthefollowingstatementisrightaccordingtothetext? A.Batslivethelongesttimeamonganimals. B.Europeanresearcherswanttofighttheagingprocessinhumanbeing. C.Fromtheinformationscientistsfoundthegreatermouse﹣earedbatlivedthelongestlifeinallspecials. D.Scientistshavedevelopedwaystofightagingbystudyingbats. 2Accordingtothescientiststelomeresare? A.structureswhichprotecttheendsofchromosomes. B.geneswhichcanbefoundinthenucleusofcells. C.chromosomeswhichcanshorteneachtimeacelldivides. D.agingprocesses. 3AccordingtothetextMyotishadthelongestlifeamongbatsspeciesbecause? A.theyhadtelomeresthatkeepageprocessing. B.theircellscanmaintainandrepairtheirtelomeres. C.theirchromosomesweremorethanothers. D.theirtelomerescausecellstobreakdown
假定英语课上老师要求同桌之间交换修改作文请你修改你同桌写的以下作文.文中共有10处语言错误每句中最多有两处.每处错误仅涉及一个单词的增加删除或修改. 增加:在缺词处加一个漏字符号∧并在其下面写出该加的词. 删除:把多余的词用斜线\划掉. 修改:在错的词下画一横线并在该词下面写出修改后的词. 注意:1.每处错误及其修改均仅限一词; 2.只允许修改10处多者从第11处起不计分. DearTerry Howareyoudoing?Inyourlastletteryouaskedmeforpart﹣timeworkinyoursummerholiday.NowIamwritingtotellyoumyopinions. Tobeginwithyoucanmakesomepocketmoneythathelpsdevelopasenseofindependent.Besidesyoucanlearnwhattodealwithvariousproblemsintheworkplace.What'smoreyoucanbuildnewfriendshipandimprovedbettersocialskills. Butasamiddleschoolstudentlearnisveryimportantforyou.Youshouldmakefulltheuseoftheholidaytostudy.Myadviceisthis:makeadetailedplanforyourstudybutworkandmanagethingsproper. Wishyouapleasantsummer. Yours LiHua
家兔中獭兔的毛纤维长度比普通兔短家兔的毛色和长度受两对等位基因控制．海狸色獭兔与青紫蓝普通兔杂交F1相互交配F2表现型及比例为灰色普通兔青紫蓝普通兔海狸色獭兔青紫蓝獭兔＝9331．相关叙述错误的是
科研人员调查了白天气温与八角金盘花丛中昆虫数昆虫体温的关系结果如图．相关叙述正确的是
假如你是李华今年暑假你将去英国CliftonSchool学习一个月并将寄宿在英国学生Jack家中.写一封电子邮件向他介绍自己并询问几个问题1.住宿方式2.能否上网3.饮食方式4.到校的交通 注意:1.词数100左右可适当增加内容2.开头和结尾已给出不计入总词数 DearJack IamLiHuaahighschoolstudentfromChina.……… Yours LiHua
我国是一个严重缺水的国家大家应倍加珍惜水资源节约用水．据测试没拧紧的水龙头每秒钟会滴下2滴水每滴水约0.05毫升．小明同学在洗手后没有把水龙头拧紧当小明离开4小时后水龙头滴了多少毫升水结果用科学记数法表示
棉花栽培中适时打顶去顶芽是棉花高产栽培的关键技术之一．打顶解除了顶端优势会改变棉株的生长中心影响植株体内光合产物和矿质养分的分配但打顶后棉株叶片在花铃后期出现早衰现象．科研人员研究了打顶后涂抹NAA对长绒棉结铃和产量的影响结果如表．请回答 注N0打顶后立即将空白羊毛脂放在切口N1打顶后立即将含浓度为3×10﹣3mmol•L﹣1NAA的羊毛脂放在切口N2打顶后立即将含浓度为3×10﹣2mmol•L﹣1NAA的羊毛脂放在切口． 1顶端优势体现了生长素生理作用具有． 2处理②和③的实验结果相差不大说明．处理④棉株的单株产量较高的原因是外源适宜浓度的NAA能提高结铃数和成铃率． 3打顶后涂抹一定浓度的NAA既保证了打顶后棉株体内的合理的生长素水平有利于更多的光合产物分配到器官又可避免因不打顶使棉株具有旺盛的顶端生长优势从而使养分过多消耗在器官上． 4为探究打顶后棉叶出现早衰现象的原因科研人员在花铃后期检测了处理①②④组的棉株叶片内相关植物激素的含量变化结果如图．据图分析叶片出现早衰现象的原因是同时说明植物生命活动是多种激素的结果． 5综合研究结果对棉花生产的指导意义是．
TwoyearsagoattheBritishAcademyofFilmandTelevisionArtsteapartyinLosAngelesMillieBobbyBrownwasacharmingdarling.WhenevershemetsomeoneshewouldextendherhandandsayHi!I'mMillieBobbyBrown.Sogladtomeetyou! BestknownforstarringasElevenayounggirlwithpsychokineticabilitiesinthehitsci﹣fiTVseriesStrangerThingsBrownisaniconforhergenerationasWmagazineputit. ToplayElevenBrownhadtocutoffherlonghairandshaveherheadwhichissomethingthatwouldbequitedifficultforanyteenager.ButtheBritishactressdiditwithoutasecondthought.Thisisperhapswhatsetsherapartfromfellowchildstars.Ontheonehanditwascool.Whenyou'rebaldrainfeelslikeaheadmassage.I'dwalkintherainandpeoplewouldlookatmelikeIwascrazyshetoldWButontheotherhandpeoplestaredatmewonderingwhetherIwassick.SomewouldevenlaughatmewithoutknowingwhetherIwasorwasn'tsick. ThesepeoplecertainlyhurtBrownesfeelingsbuttheyalsotaughthersomethingaboutcompassion.IntheendbeingbaldwasthebestthingIeverdid﹣beingdifferentchangedmylife.Iwantedtoembracemybaldnessandhopefullyinspirepeopleshesaid. HerbraverywonherthehonoroftheyoungestUNICEFGoodwillAmbassadorlastmonth. It'sahugehonortobecomeUNICEF'snewestandyoungesteverGoodwillAmbassadorthe14﹣year﹣oldwhohassupportedthechildren'scharitysince2016wroteonsocialmediaplatformInstagram.IamlookingforwardtomeetingasmanychildrenandyoungpeopleasIcanhearingtheirstoriesandspeakingoutontheirbehalf. ChildrenaretheirownbestadvocatesHenriettaForeUNICEF'sexecutivedirectorsaidinanannouncement.IknowthatMilliewilluseherpassiontodefendtherightsofvulnerablechildrenandyoungpeopleeverywhere. 1FromthepassageweknowthatMillieis. A.conservative B.aggressive C.outgoing D.energetic 2WhatdidMilliedotoplaywellinStrangerThings? A.Shetiedupherlonghair. B.Shemadeherheadbald. C.Shelearnedfromotherfellowstars. D.Sheshavedherbody. 3WhichstatementisTRUEaccordingthepassage? A.Milliewasgreatlyencouragedbyothers. B.Milliedidn'tregrettedbeingshaved. C.Milliewasinspiredbyallkindsofcomments. D.Milliewasdiscouragedbymisunderstanding. 4What'sHenriettaFore'sopinionaccordingtothepassage? A.Millieissuretohelpthevulnerablechildrenaroundtheworld. B.ChildrenareMollie'sbestadvocates. C.Milliewilldoherbesttodefendagainstvulnerablechildren. D.Therearesomanyvulnerablechildrenandyoungpeopleintheworld.
把下列数据用科学记数法表示出来地球离太阳约有1亿5千万千米
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