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在直角坐标平面内，以坐标原点O为极点，x轴的非负半轴为极轴建立极坐标系．已知点A、B的极坐标分别为、，曲线C的参数方程为为参数）． （Ⅰ）求直线AB的直角坐标方程； （Ⅱ）若直线AB和曲线C只有...
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高三上学期数学《》真题及答案
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若曲线的极坐标方程为ρ＝2sinθ＋4cosθ以极点为原点极轴为x轴正半轴建立直角坐标系则该曲线的直
在直角坐标平面内以坐标原点O.为极点x轴的非负半轴为极轴建立极坐标系.已知点A.B.的极坐标分别为曲
在直角坐标系xOy中曲线C的参数方程为t为参数在以原点O为极点x轴的非负半轴为极轴建立极坐标系．直
在极坐标系中曲线C.1和C.2的方程分别为和＝1以极点为平面直角坐标系的原点极轴为x轴的正半轴建立平
己知在平面直角坐标系xOy中圆O的参数方程为α为参数.以原点O为极点以x轴的非负半轴为极轴的极坐标系
已知直角坐标系中直线l的参数方程为.以直角坐标系xOy中的原点O.为极点x轴的非负半轴为极轴圆C.的
曲线C.的直角坐标方程为x2＋y2－2x＝0以原点为极点x轴的正半轴为极轴建立极坐标系则曲线C.的极
已知极坐标系的极点在平面直角坐标系的原点O处极轴与x轴的非负半轴重合且长度单位相同若圆C的极坐标方程
在平面直角坐标系中以坐标原点为极点x轴的非负半轴为极轴建立坐标系.已知点A.的极坐标为直线l的极坐标
在平面直角坐标系中以坐标原点 O 为极点以 x 轴的非负半轴为极轴建立极坐标系将直角坐标系下的方程
在平面直角坐标系xoy中圆C.的参数方程为t为参数.在极坐标系与平面直角坐标系xoy取相同的长度单位
在平面直角坐标系xOy中圆C.的参数方程为在以原点O.为极点x轴的非负半轴为极轴建立的极坐标系中直线
已知曲线C.1在平面直角坐标系中的参数方程为t为参数以坐标原点O.为极点x轴的非负半轴为极轴建立极坐
在平面直角坐标系中以坐标原点为极点x轴的非负半轴为极轴建立极坐标系.已知曲线C.的极坐标方程为ρ=4
已知平面直角坐标内两点A02B−40AB的中点是M以原点为极点x轴正半轴为极轴建立极坐标系则M的极坐
已知曲线C.的极坐标方程为ρ＝2cosθ以极点为原点极轴为x轴的正半轴建立直角坐标系则曲线C.的参数
在平面直角坐标系xOy中直线l的参数方程为t为参数P.Q.分别为直线l与x轴y轴的交点线段PQ的中点
已知曲线C的极坐标方程为4ρ2cos2θ+9ρ2sin2θ=36以极点为平面直角坐标系的原点极轴为x
已知直角坐标系xOy中直线l的参数方程为.以直角坐标系xOy中的原点O.为极点x轴的非负半轴为极轴圆
在直角坐标系xOy中以原点O.为极点x轴的正半轴为极轴建立极坐标系.已知射线θ＝与曲线t为参数相交于
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下列实验装置图正确的是
如图所示AB为相互接触的用绝缘柱支撑的金属导体起初它们不带电在它们的下部贴有金属箔片C是带正电的小球下列说法正确的是 A．把C移近导体A时AB上的金属箔片都张开 B．把C移近导体A时先把AB分开然后移去导体CAB上的金属箔片仍张开 C．先把C移走再把AB分开AB上的金属箔片仍张开 D．先把AB分开再把C移走然后重新让AB接触A上的金属箔片张开而B上的金属箔片闭合
InChinawecanseeeverywherethatsomepedestrianstendtoruntheredlightingroupswhencrossingthestreet.ThisphenomenonhasattractedwidespreadconcerninChina.RecentlyBeijinggovernmentannouncedthatpeoplewhodonotwaitforthegreenlighttocrosstheroadwillreceiveafineof10yuan.What'smoreusingthediagonaltocrosstheroadisalsoagainsttherules.WalkersshouldwalkinanLshape. BesidesBeijingmanyplaceshavealsotakenstepstostopChinesestyleroadcrossing.ProvincessuchasSichuanShanxiandZhejianghavealreadystartedtofinejaywalkers5to50yuansincelastyear.Thispunishmentcancallonpeopletorealizetheimportanceoftrafficsafety.Howevermanypeoplecomplainthattheredlightslasttoolong.EveryoneshouldfollowtherulesorthecountrywillloseitsordersaidPeopleDaily. Somecitieshavealsopaidattentiontotheproblem.ForexampleBeijinggovernmentsaiditshouldnotonlypunishthesejaywalkersbutalsoimproveroadsafetyfacilitiessuchasproperlyfixingtrafficlightsandbuildingoverpasses. Anyhowsafetymustcomefirst. 【写作内容】 1.以约30个词概括上文的主要内容; 2.以约120个词发表你对中国式过马路的看法内容包括: 1指出由此造成的影响; 2分析出现这种现象的原因; 3针对这个现象提出建议. 【写作要求】 1.作文中可以使用亲身经历或虚构的故事也可以参照阅读材料的内容但不得直接引用原文中的句子. 2.作文中不能出现真实姓名和学校名称. 【评分标准】 概括准确语言规范内容合适语篇连贯. .
A.IAmaPencil SamSwope'sjobwasteachingwritingtothird﹣gradersinNewYorkCity.Hisstudentswerefrom21countriesspeaking11languageswithdifferentbackgrounds.Buttherewereafewthingstheyhadincommon.Familytroubles.Moneystruggles.Andpoetry.Everysinglestudentwiththehelpofthiscreativeteachercameforthwithawesomewriting. B.BetweenaRockandaHardPlace AronRalston28wenthikinginaremoteUtahcanyonwithouttellinganyone. Anunexpectedcatastrophestruck.WithoutenoughsuppliesRalstonknewhissituationwasfullofdanger.Afterfivedayshewasinafightagainstdeath.Thatwaswhenhecarriedoutacourageousplan.Hisamazingsurvivalstoryrestsataplaceamongtheclassicsofthegenre. C.OurBrother'sKeeper AuthorJedwinSmithspent30yearstryingtoholdbackallmemoriesofhisbrotherJeffwhowaskilledinVietnam.ButinOurBrother'sKeeperhetellswhathappenswhentheInternetbringshimintocontactwithseveralhisbrother'soldMarinefriendsincludingtheguywhoheldJeffinhisarmsashedied.Firstviae﹣mailandtheninpersonSmithgetstoknowthesemen. D.TheAllAmericans WithhisgraduationfromWestPointHenryRomaneksailedtowardOmahaBeachontheeveofD﹣day.ItwasJune1944andhewasabouttofacethebloodiestbattleofhislife.JustyesterdayitseemedhewasastandoutsoldierontheArmyteam.Nowhewasaleaderofyoungstersinbattlefightingforhiscountryandthefutureofthefreeworld. E.CopiesinSeconds Withthepushofabuttonanyonecanmakecopiesofalmostanything.InCopiesinSecondsDavidOwenshowedhowashyengineernamedChesterCarlsonperfectedhisxerographymachineandshoppeditarounduntilfinallyhookingupwiththeHaloidCorporation.ThatpartnershipledtotheXeroxcopierandchangedthefaceofworkforever. F.StateofGrace Backinthelate1950sandearly1960stheLynvetswasjustafoot﹣ballteaminasandyNewYorkCityneighborhood.Buttomostofitsmemberstheteamwastheironlyexperienceofahappyfamilytheironlychancetoriseabovebadeverydaycircumstancestheironlyshotatbeingheroes.Thefriendshipsthesemenformedsustainedthemthroughouttheirlives. 请阅读以下求书者的信息然后匹配他们所要寻找的书籍: 1.Kateisdoingresearchintohistory.RecentlyshebecomesinterestedinthehistoryaboutWorldWarII.Shenowwantstofindabookaboutthestoriesofthesoldiersatthattime. 2.Tomisateacherandinterestedinhikingandclimbingverymuch.Nowheislookingforabookaboutthehikingstoriestohelphiminhisfollowingoutdooractivities. 3.Jackisresearchingintoeducationinacollege.Heisespeciallyinterestedintheteachingmethods.Hewantstofindabookwhichcantellhimsomethingabouthowtoteachstudentsfromdifferentbackgrounds. 4.Johnisanexpertonmilitaryaffairs.HewantstofindsomematerialsaboutthesoldiersinVietnamWartocarryonhisnewresearch. 5.Markisstudyingscience.Nowadayshewantstoresearchintothehistoryoftechnologicaldevelopment.Hefirsthopestofindabookaboutthedevelopmentofthecopierswhichhavechangedourworldgreatly.
氢气是新型能源和重要化工原料． 已知①2COg+O2g＝2CO2g△H1 ②CH4g+2O2g＝CO2g+2H2Ol△H2 ③H2g+O2g＝H2Ol△H2 1科学家提出一种利用天然气制备氢气的方法CH4g+CO2g＝2COg+2H2g△H △H＝．这种方法的推广与使用不仅实现资源综合利用而且还能解决环境问题是． 2氨气是重要化工原料在国民经济中占重要地位． ①在恒温容积相等的恒容密闭容器中投入一定量氮气氢气发生如下可逆反应 N2g+3H2g═2NH3g△H＝﹣92.4kJ•mol﹣1 实验测得起始平衡时的有关数据如表所示 下列判断正确的是． A．N2的转化率Ⅱ＞I＞Ⅲ B．放出热量a＜b＜92.4n C．达到平衡时氨气的体积分数Ⅲ＞Ⅰ D．平衡常数Ⅲ＞Ⅱ＞Ⅰ ②在密闭恒容容器中投入一定量氮气和氢气混合气体中氨气体积分数和温度关系如图所示 曲线TJ段变化主要原因是JL段变化的主要原因是．氨气正反应速率T点L点填大于小于或等于． ③在2L密闭容器中充入一定量的氨气氨气的物质的量与反应时间关系如表所示 在该条件下前5分钟H2平均反应速率为． ④常温下在VmL的amol•L﹣1稀硫酸溶液中滴加bmol•L﹣1稀氨水VmL恰好使混合溶液呈中性．此时一水合氨的电离常数Kb＝用含ab代数式表示． 3氢气直接作燃料电池的理论输出电压为1.2V能量密度E＝ ＝32.2kW•h•kg﹣1列式计算．
玉米细胞中与籽粒种皮的颜色有关的两对等位基因B和bD和d位置如图所示基因B控制色素的形成．一般情况下当基因B存在时籽粒种皮有色否则就表现无色基因D会抑制基因B的表达使基因B不能控制合成色素籽粒种皮表现为无色． 1不考虑基因突变和交叉互换的情况下图中基因①为选填“D”“d”“B”或“b”I和Ⅱ是一对具有图中这种基因组成的玉米籽粒种皮的颜色为． 2现有一株纯种的籽粒有色玉米BBdd与一株纯种的籽粒无色玉米杂交若F1全为有色则亲代籽粒无色玉米的基因型为若不考虑交叉互换F1自交产生F2F2籽粒种皮颜色和比例为． 3研究发现当A基因存在时D基因会从染色体上断裂脱落下来从而解除其对基因B的抑制基因B得以表达籽粒种皮表现出色斑．若图中ⅠⅡ处a突变成A则与籽粒种皮颜色相关的基因型为AaBb该植株自交后代籽粒种皮表现型及比例是．
AyearagoAugustDaveFusslosthisjobdrivingatruckforasmallcompanyinwestMichigan.HiswifeGerriewasstillworkinginthelocalschoolcafeteriabutworkforDavewasscarceandthepriceofeverythingwasrising.TheFusseswereatriskofjoiningthemillionsofAmericanswhohavelosttheirhomesinrecentyears.ThenDaveandGerriereceivedatimelygift﹣7000alegacy遗产formtheirneighborsIshandArleneHatchwhodiedinanaccident.Itreallymadeadifferencewhenweweregoingunderfinancially.saysDave. ButtheFussesweren'ttheonlyfolksinAltoandtheneighboringtownofLowelltoreceiveunexpectedlegacyfromtheHatches.DoxensofotherfamiliesweretouchedbytheHatches'generosity.Insomecasesitwasafewthousanddollars;inotheritwasmorethan100000. ItsurprisednearlyeveryonethattheHatcheshadsomuchmoneymorethan3million﹣theywereamelderlycouplewholivedinanoldhouseonwhatwasleftofthefamilyfarm.ChildrenoftheGreatDepressionIshandArlenewereknownfortheirhabitofsavingTheythrivedown喜欢comparisonshoppingandwouldroutinelygofromstoretostorecheckingpricesbeforemakinganewpurchase. ThroughtheyearstheHatchespaidforlocalchildrentoattendsummercampwhentheirparentscouldn'taffordit.IshandArleneneveraskedyouneededanythingsaystheirfriendSandVanWeeldenThey'dseethingstheycoulddogomakeyouhappierandthey'lldothem. EvenmoreextraordinarywasthattheHatcheshadtheirfarmlanddistributed.ItwastheHatches'wishthattheirlegacy﹣alegacyofkindnessasmuchasoneofdollarsandcent﹣shouldenrichthewholecommunityandIshandArleneHatch'sstory. Neighborshelpingneighbors﹣﹣thatwasIshandArleneHatch'sstory. 1.AccordinggothetexttheFusses. A.wereemployedbyatruckcompany B.wereinfinancialdifficulty C.workedinaschoolcafeteria D.losttheirhome 2.WhichofthefollowingistrueoftheHatches? A.TheyhadtheirchildrenduringtheGreatDeoression B.Theyleftthefamilyfarmtoliveinanoldhouse C.Theygaveawaytheirpossessionstotheirneighbors D.Theyhelpedtheirneighborstofindjobs 3.WhywouldtheHatchesroutinelygofromstore? A.Theydecidedtoopenastore B.Theywantedtosavemoney C.Theycouldn'taffordexpensivethings D.Theywantedtobuygiftsforlocalkids 4.AccordingtoSandVanWeeldentheHatcheswere. A.understanding B.optimistic C.childlike D.curious 5.Whatcanwelearnfromthetext? A.ThecommunityofAltowaspoor B.Thesummercampwasattractivetotheparents C.SandyVanWeeldengotalegacyformtheHatches D.TheHatcheswouldliketheneighborstofollowtheirexample
用体外实验的方法可合成多肽链．已知苯丙氨酸的密码子是UUU若要在体外合成同位素标记的多肽链所需的材料组合是 ①同位素标记的tRNA ②蛋白质合成所需的酶 ③同位素标记的苯丙氨酸 ④人工合成的多聚尿嘧啶核苷酸 ⑤除去了DNA和mRNA的细胞裂解液
在探究影响电荷间相互作用力的因素时有图示实验系在丝线上的带正电的小球A恰与带正电的物体B等高而处于静止状态丝线与竖直方向的夹角为θ．则 A．若仅减小A的电量θ将保持不变 B．若仅减小B的电量θ将保持不变 C．改变B的电量上下移动B的位置使θ不变则A受到的库仑力不变 D．改变B的电量左右移动B的位置使θ不变则A受到的库仑力不变
用NA表示阿伏加德罗常数下列说法正确的是
海水中含有丰富的锂资源研究人员开发了一种只能让锂离子通过的特殊交换膜并运用电解实现从海水中提取高浓度的锂盐其工作原理如图所示｡下列说法不正确的是
LastSundaymytrainwasdelayedfortwohours.Ihadplentyoftimeto1.AfterbuyingsomenewspaperstoreadonthejourneyImademywaytothe2officetocollectmyheavysuitcaseIhadlefttherethreedaysbefore.Therewereonlyafewpeople3andItookoutmywallettofindthereceiptformycase.Thereceiptdidn'tseemtobewhereIhadleftit.I4thecontentsandrailwayticketsmoneyscrapsofpaperandphotosfelloutofit.ButnomatterhowhardIsearchedthe5wasnowheretobefound. WhenmyturncameIexplainedthesituation6totheassistant.Themanlookedatmeupanddownasiftosaythathehadheardthiskindofsadstorymanytimesandaskedmeto7thecase.Itoldhimthatitwasanoldbrownlooking8nodifferentfromthemanycasesIcouldseeontheshelves.Theassistantthengavemean9andtoldmetomakealistofthechiefcontentsofthecase.Iftheywere10hesaidIcouldtakethecaseaway.ItriedtorememberallthearticlesIhad11packedintothecaseinashorttimeandwrotethemdownastheycametome. AfterIhaddonethisIwentto12amongtheshelves.Therewerehundredsofcasesthere.Foronedreadfulmomentit13tomethatifsomeonehadpickedthereceiptuphecouldhaveeasilyclaimedthecasealready.Thishadn'thappened14forafteratimeIfoundthecaselyinginacorner.Afterexaminingthearticlesinsidetheassistantwas15andtoldmeIcouldtakethecaseaway. 1.A.waste B.spare C.arrange D.make 2.A.tourist B.luggage C.ticket D.head 3.A.standing B.crowding C.talking D.waiting 4.A.threw B.gathered C.checked D.emptied 5.A.newspaper B.receipt C.case D.shelf 6.A.easily B.excitedly C.gladly D.sorrowfully 7.A.describe B.draw C.examine D.show 8.A.object B.bag C.pocket D.wallet 9.A.address B.envelope C.message D.form 10.A.good B.wrong C.correct D.ready 11.A.carelessly B.suddenly C.hurriedly D.immediately 12.A.look B.watch C.find D.see 13.A.happened B.occurred C.appeared D.seemed 14.A.fortunately B.unluckily C.hopefully D.presently 15.A.disappointed B.surprised C.satisfied D.worried
下列关于细胞中能量代谢的叙述错误的是
在真空中两个点电荷带有相等的电荷量要求它们之间相距1m时的相互作用力等于1N若静电力常量k＝9×109Nm2/C2则每个电荷的电荷量是多少等于电子电荷量的多少倍
Plantscan'tcommunicatebymovingormakingsoundsasmostanimalsdo.Insteadplantsproducevolatilecompoundschemicalsthateasilychassefromaliquidtoagas.Aflower'ssweetsmellforexamplecomesfromvolatilecompoundsthattheplantproducestoattractinsectssuchasbugsandbees. PlantscanalsodetectvolatilecompoundsproducedbyotherplantsAtreeunderattackbyhungryinsectsforinstancemaygiveoffvolatilecompoundsthatletothertreesknowabouttheattack.Inresponsetheothertreesmaysendoffchemicalstokeepthebugsaway﹣﹣﹣orevenchemicalsthatattractthebugs'naturalenemies. Nowscientistshavecreatedaquickwaytounderstandwhatplantsaresaying:achemicalsensor传感器calledanelectronicnose.Thee﹣nosecantellcompoundsthatcropplantsmakewhenthey'reattacked.Scientistssaythee﹣nosecouldhelpquicklydetectwhetherplantsarebeingeatenbyinsects.Buttodaytheonlywaytodetectsuchinsectsistovisuallyinspectindividualplants.Thisisachallengingtaskformanagersofgreenhousesenclosedgardensthatcanhousethousandsofplants. Theresearchteamworkedwithane﹣nosethatrecognizesvolatilecompounds.Insidethedevice13sensorschemicallyreactwithvolatilecompounds.Basedontheseinteractionsthee﹣nosegivesoffelectronicsignalsthatthescientistsanalyzeusingcomputersoftware. Totestthenosetheteampresenteditwithhealthyleavesfromcucumberpepperandtomatoplantsallcommongreenhousecrops.Thenthescientistscollectedsamplesofairarounddamagedleavesfromeachtypeofcrop.Theseplantshadbeenchangedbyinsectsorbyscientistswhomadeholesintheleaveswithaholepunch打孔器. Thee﹣noseitturnsoutcouldidentifyhealthycucumberpepperandtomatoplantsbasedonthevolatilecompoundstheyproduce.Itcouldalsoidentifytomatoleavesthathadbeendamaged.Butevenmoreimpressivethedevicecouldtellwhichtypeofdamage﹣byinsectsorwithaholepunch﹣hadbeendonetothetomatoleaves. Withsomefine﹣tuningadevicelikethee﹣nosecouldonedaybeusedingreenhousestoquicklyspotharmfulbugstheresearcherssay.AdevicelikethiscouldalsobeusedtoidentifyfruitsthatareperfectlyripeandreadytopickandeatsaysNataliaDudareveabiochemistatPurdueUniversityinWestlafayetteInd.whostudiessmellsofflowersandplants.Hopefullyscientistsbelievethedevicecouldbringlargebenefitstogreenhousemanagersinthenearfuture. 1.Welearnfromthetextthatplantscommunicatewitheachotherby. A.makingsomesounds B.wavingtheirleaves C.producingsomechemicals D.sendingoutelectronicsignals 2.Whatdidthescientistsdotofindoutifthee﹣noseworked? A.Theypresenteditwithallcommoncrops. B.Theyfixed13sensorsinsidethedevice. C.Theycollecteddifferentdamagedleaves. D.Theymadetestsondamagedandhealthyleaves. 3.Accordingtothewriterthemostamazingthingaboutthee﹣noseisthatitcan. A.pickoutripefruits B.spottheinsectsquickly C.distinguishdifferentdamagestotheleaves D.recognizeunhealthytomatoleaves 4.Wecaninferfromthelastparagraphthatthee﹣nose. A.isunabletotellthesmellofflowers B.isnotyetusedingreenhouses C.isdesignedbyscientistsatPurdue D.ishelpfulinkillingharmfulinsects 5.Whichsectionofnewspaperdoesthepassageprobablybelongto? A.Sport B.Life C.Discovery D.Entertainment
Cancerisfearedbyeveryone.Andthisfearisreachingepidemic流行性proportions.Notthediseaseitself﹣thereisnosuchthingasacancerepidemic.Exceptforlungcancermostlycausedbycigarettesmokingtheincidencerates发病率arelevelingoffandinthecaseofsomekindsofcanceraredecreasing.ButthefearofcanceriscatchingandthecountrystandsatriskofananxietyTheearthitselfiscomingtoseemlikeahugecarcinogen致癌物.Theordinarymoreorlessscientificstatementthatsomethingbetween80and90percentofallcancersareduetothingsintheenvironmentistakentomeanthatnoneofuswillbesafeuntilthewholeenvironmentiscleanedup.Thisisnotatallthemeaning. The80﹣percentcalculationisbasedontheunthinkabledifferencesintheincidenceofcancerinvarioussocietiesaroundtheworld﹣forexamplethehighproportionoflivercancerinAfricaandtheFarEaststomachcancerinJapanbreastcancerinWesternEuropeandNorthAmericaandtherelativelylowfiguresforbreastcancerinJapanandpartsofAfricaandforlivercancerinAmerica.Thesedataindicatetheremaybespecialandspecificenvironmentalinfluenceslargelybasedonpersonallife﹣stylethatdeterminetheincidenceofvariousformsofcancerindifferentcommunities﹣butthatisallthedatasuggest.Theoverallincidenceofcancercountingupallthecasesisprobableroughlythesameeverywhere. 1.Whichofthefollowingisclosesttomeaningtothephraselevelingoff? A.Becameverypopular B.Reacheditslowestlevelinpopularity C.Stoppedbeingpopular D.Stoppedincreasingitspopularity 2.Accordingtothepassagetheincidenceofcancerisgenerallybelieved A.tobebasedoninactivelifestyle B.tobeduetoanxiety C.toresultfromenvironmentalinfluences D.tobecausedbyheavysmoking 3.Itcanbeinferredfromthepassagethatthewriter'sopinionabouttherelationshipbetweencancerandenvironmentis. A.positive B.negative C.neutral D.approving 4.Accordingtothepassagethewriterseemstofeelthat. A.theriskofcatchingcancerisontherise B.thewholeearthiscomingtoseemlikeahugecarcinogen C.theriskofcatchingcancerisn'tsogreataspeoplethink D.cancercanbecurediftheenvironmentiscleanedup 5.Whichofthefollowingwouldbethebesttitleforthepassage? A.CancerandEnvironment B.TheFearCausedbyCancers C.DataonCancerIncidence D.CanceranditsInvestigation
研究表明蛙未受精卵细胞的细胞质中储存有大量的mRNA．蛙卵在生理盐水中能正常合成mRNA而物质甲会抑制mRNA的合成．通过设计实验检测蛋白质合成量探究蛙受精卵早期分裂过程中20小时内蛋白质合成所需要的mRNA来源于卵细胞中原本储存的mRNA还是卵细胞受精后新合成的．下列相关叙述正确的是
人的排尿是一种反射活动．回答下列问题． 1膀胱中的感受器受到刺激后会产生兴奋．兴奋从一个神经元到另一个神经元的传递是单向的其原因是． 2排尿过程的调节属于神经调节神经调节的基本方式是反射．排尿反射的初级中枢位于．成年人可以有意识地控制排尿说明排尿反射也受高级中枢控制该高级中枢位于． 3排尿过程中尿液还会刺激尿道上的从而加强排尿中枢的活动促进排尿．
如图是不同浓度的24﹣D溶液对洋葱生根影响的实验结果分析正确的是
基因工程中可以通过PCR技术扩增目的基因．回答下列问题． 1基因工程中所用的目的基因可以人工合成也可以从基因文库中获得．基因文库包括和． 2生物体细胞内的DNA复制开始时解开DNA双链的酶是．在体外利用PCR技术扩增目的基因时使反应体系中的模板DNA解链为单链的条件是．上述两个解链过程的共同点是破坏了DNA双链分子中的． 3目前在PCR反应中使用Taq酶而不使用大肠杆菌DNA聚合酶的主要原因是．
最常见的塑化剂邻苯二甲酸二丁酯可由邻苯二甲酸酐与正丁醇在浓硫酸共热下反应制得反应的化学方程式及装置图部分装置省略如图 +C4H9OH 已知正丁醇沸点118℃纯邻苯二甲酸二丁酯是无色透明具有芳香气味的油状液体沸点340℃酸性条件下温度超过180℃时易发生分解． 由邻苯二甲酸酐正丁醇制备邻苯二甲酸二丁酯实验操作流程如下 ①向三颈烧瓶内加入30g0.2mol邻苯二甲酸酐22g0.3mol正丁醇以及少量浓硫酸． ②搅拌升温至105℃持续搅拌反应2小时保温至反应结束． ③冷却至室温将反应混合物倒出．通过工艺流程中的操作X得到粗产品． ④粗产品用无水硫酸镁处理至澄清→取清液粗酯→圆底烧瓶→减压蒸馏经过处理得到产品20.85g． 请回答以下问题 1步骤②中不断从分水器下部分离出产物水的目的是．判断反应已结束的方法是． 2上述实验可能生成的副产物的结构简式为填一种即可 3操作X中应先用5%Na2CO3溶液洗涤粗产品．纯碱溶液浓度不宜过高更不能使用氢氧化钠若使用氢氧化钠溶液对产物有什么影响用化学方程式表示． 4操作X中分离出产物的操作中必须使用的主要玻璃仪器有． 5粗产品提纯流程中采用减压蒸馏的目的是． 6本实验中邻苯二甲酸二丁酯式量是278的产率为．
干扰素能抑制病毒的复制可增强巨噬细胞和T淋巴细胞的活力从而起到免疫调节作用．下图是利用基因工程技术生产干扰素的操作过程示意图请据图回答． 1图中①代表的是过程所获得的甲是． 2在生物体外重复②③④的步骤可以获得大量的甲这是技术．其中过程③需要酶． 3与人体细胞中干扰素基因相比甲不含有非编码区和． 4在利用甲乙获得丙的过程中必须用同一种切割甲和乙使它们产生相同的再加入连接形成丙． 5科学家将甲与的启动子等调控组件重组在一起形成的基因表达载体通过方法导入到哺乳动物的中进行早期胚胎培养当胚胎发育到阶段时进行胚胎移植同时__母体对移入子宫的胚胎基本上不发生才为移入的胚胎在__母体内的成活提供了可能使其生长发育成转基因动物．该动物进入泌乳期后可以通过分泌的乳汁中获得．
动物受到惊吓刺激时兴奋经过反射弧中的传出神经作用于肾上腺髓质使其分泌肾上腺素兴奋还通过传出神经作用于心脏．下列相关叙述错误的是
Nooneknowsexactlyhowmanydisabledpeoplethereareintheworldbutestimatessuggestthefigureisover450million.ThenumberofdisabledpeopleinIndiaaloneisprobablymorethandoublethetotalpopulationofCanada. IntheUnitedKingdomaboutoneintenpeoplehavesomedisability.Disabilityisnotjustsomethingthathappenstootherpeople.Aswegetoldermanyofuswillbecomelessmobilehardofhearingorhavefailingeyesight. Disabilitycantakemanyformsandoccuratanytimeoflife.Somepeoplearebornwithdisabilities.Manyothersbecomedisabledastheygetolder.Therearemanyprogressivediseases.Thelongertimegoesontheworsetheybecome.Somepeoplearedisabledinaccidents.Manyothersmayhaveaperiodofdisabilityintheformofamentalillness.Allarebypeople'sattitudetowardsthem. Disabledpeoplefacemanyphysicalbarriers.Nexttimeyougoshoppingortoworkorvisitfriendsimaginehowyouwouldmanageifyoucouldnotgetupstepsorontobusesandtrains.Howwouldyoucopeifyoucouldnotseewhereyouweregoingorcouldnothearthetraffic?Butthereareotherbarriers:prejudicecanbeevenhardertobreakdownandunavoidablyrepresentsbyfarthegreatestbarrierofall.Itisalmostimpossiblefortheable﹣bodiedtofullyappreciatewhatthedisabledgothroughsoitisimportanttodrawattentiontothesebarriersandshowthatitistheindividualpersonandtheirabilitynottheirdisabilitywhichcounts. 1.Thefirstparagraphpointsoutthat. A.itispossibletogetanexactfigureoftheworld'sdisabledpeople B.therearemanydisabledpeopleintheworld C.thenumberofdisabledpeopleinIndiaisthegreatest D.IndiahasnotmuchmoredisabledpeoplethanCanada 2.ThekeywordinParagraph4is. A.barriers B.ignorance C.disability D.prejudice 3.Thelastwordofthepassagecountsmostprobablymeans. A.ismostimportant B.isincluded C.isconsidered D.isnumbered 4.WhichofthefollowingstatementsisNOTtrueaccordingtothepassage? A.eventheable﹣bodiedmaybecomedisabledinsomeway B.thedisabledprefertobeignoredbytheable﹣bodied C.prejudiceagainstthedisabledshouldberemoved D.Thedisabledmakeupabout10percentintheUK'spopulation 5.Itcanbeconcludedfromthepassagethat. A.weshouldtryourbesttopreventdisability B.wemusttakeaproperattitudetowardsthedisabled C.theable﹣bodiedpeoplewillneverfullyunderstandthedisabled D.bothphysicalandmentalbarriersarehardtobreakdown.
如图为神经系统内分泌系统与免疫系统之间相互关系的样例示意图据图回答． 1神经系统内分泌系统与免疫系统之间的信息分子存在着填“单向”或“双向”调节作用．图中神经系统内分泌系统免疫系统各自产生的信息分子分别是填序号和免疫活性物质可直接与靶细胞细胞膜表面的结合． 2焦虑紧张等应激刺激使下丘脑分泌的激素含量升高最终导致血液中肾上腺糖皮质激素的浓度使免疫功能受抑制因此肾上腺糖皮质激素可以用于以下填字母的治疗 a．系统性红斑狼疮b．艾滋病c．过敏反应d．器官移植e．先天性胸腺发育不良 3三大系统相互配合借助信息分子相互作用构成了调节网络共同维持内环境的稳态．例如成年人甲状腺激素分泌过量会使神经系统的加强．
Therearemomentsinlifewhenyoumisssomeonesomuchthatyoujustwanttopickthemfromyourdreamsandhugthemforreal!Dream1youwanttodreambecauseyouhaveonlyonelifetodoallthethingsyouwanttodo. Mayyouhaveenoughhappinesstomakeyousweetandenoughtrialstomakeyoustrong?Alwaysput2inothers'shoes.Ifyoufeelthatithurtsyouitprobablyhurtstheotherpersontoo. Thehappiestofpeopledon't3necessaryhavethebestofeverything.Theyjustmakethemostofeverything4comesalongtheirway.Happinessliesforthosewho5searchandthosewhohavetriedforonlytheycanappreciatetheimportanceofpeoplewhohavetouchedtheirlives.Lovebeginswithasmilegrowswithakissandends6atear.Thebrightestfuturewillalwaysbebasedon7forgottenpast.Youcan'tgoonwellinlife8youletgoofyourpastfailuresandheartaches. Whenyouwerebornyouwerecryingandyourfamilywerearoundyou9smile.Liveyourlifesothatwhenyoudieyou'rethe10whoissmilingandeveryonearoundyouiscrying. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.
已知函数fx＝x+lnx则f′1的值为
你在本地报纸上读到对健身教练Michael的采访请你用英语向班里的同学介绍这篇报道的内容. 【写作内容】 【写作要求】 1.只能使用5个句子表达全部内容; 2.作文中不能出现真实姓名和学校名称. 【评分标准】 句子结构准确信息内容完整篇章结构连贯. .
某实验室保存有野生型和一些突变型果蝇．果蝇的部分隐性突变基因及其在染色体上的位置如图所示．回答下列问题． 1同学甲用翅外展粗糙眼果蝇与野生型正常翅正常眼纯合子果蝇进行杂交F2中翅外展正常眼个体出现的概率为．图中所列基因中不能与翅外展基因进行自由组合的是． 2同学乙用焦刚毛白眼雄蝇与野生型直刚毛红眼纯合子雌蝇进行杂交正交则子代雄蝇中焦刚毛个体出现的概率为若进行反交子代中白眼个体出现的概率为． 3为了验证遗传规律同学丙让白眼黑檀体雄果蝇与野生型红眼灰体纯合子雌果蝇进行杂交得到F1F1相互交配得到F2．那么在所得实验结果中能够验证自由组合定律的F1表现型是F2表现型及其分离比是验证伴性遗传时应分析的相对性状是能够验证伴性遗传的F2表现型及其分离比是．
某实验小组用细菌甲异养生物作为材料来探究不同条件下种群增长的特点设计了三个实验组每组接种相同数量的细菌甲后进行培养培养过程中定时更新培养基三组的更新时间间隔分别为3h10h23h得到abc三条种群增长曲线如图所示．下列叙述错误的是
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