单选题一个用35S标记了的噬菌体侵入细菌体内，经过三次复制后，测得含35S的噬菌体与子代总数的比值是（）A0B1/4C1/2D1
单选题
一个用35S标记了的噬菌体侵入细菌体内，经过三次复制后，测得含35S的噬菌体与子代总数的比值是（）
A
0
B
1/4
C
1/2
D
1
参考解析
解析：
暂无解析
相关考题：
单选题《三峡》一课，有一道课后练习：“阅读下面这首诗，你能说出它和本文之间的某些联系吗？”（附：李白《早发白帝城》：朝辞白帝彩云间，千里江陵一日还。两岸猿声啼不住，轻舟已过万重山。）对该练习的设计意图，分析不正确的是（ ）。A以散文和诗歌进行比较，培养学生的对比阅读能力B着眼于学生将两者共同含有的内容对应起来C沟通课内与课外阅读，加强语文与其他学科的联系D作为补充阅读，拓宽阅读范围，扩大学生视野
问答题课题：《和平鸽》学习领域：设计·应用教学内容：以和平为主题设计创作一幅“招贴画”。某老师的教学设计如下：①观看大屏幕展示的若干幅反映战争的图片。问：同学们，你们刚才看到了什么？看了这些图片你能想到什么？②展示若干幅毕加索的作品。又问：你看到了什么？它描写了什么内容？③展示毕加索画像，并进行生平介绍。④展示学生讨论的内容。问题一：在美术领域中我们可用哪些手段来表现自己对人类的关注？问题二：毕加索在什么情况下创作的这几幅作品？他的作品描述了什么内容？（以上教学环节用了25分钟时间）⑤展示两幅以“和平”为主题的“招贴画”。师：请同学们欣赏并将内容进行描述。多数同学回答反映的是“盼望和平”。⑥制作“招贴画”。教师简单讲述了招贴画制作方法和要求。问题：你认为此教学设计是否合理？为什么？
单选题根据音乐教学媒体的选择与使用原则，下列选项中正确的是（ ）。A教学媒体越高级，音乐教学效果就越好B网络信息技术与音乐教学无关C没有多媒体，音乐教学质量就无法提高D教学媒体不仅要选择合适，而且要使用得当，这样才能发挥教学媒体辅助教学的作用
单选题某教师阅读《义务教育语文课程标准（2011年版）》后，写了一段关于语文教学资源的理解，其中不正确的一项是（）。A教师要树立正确的课程资源观.重视生活中课程资源的开发B方言俗语、自然风光不能成为语文课程资源C教师应借助生活中的阅读资源，激发学生的阅读兴趣D教师应指导学生自主发掘课程资源，自主学习
单选题A 球进入竖直半圆弧轨道后做匀速圆周运动B 若小球能通过半圆孤最高点P.则球运动到P时向心力恰好为零C 若小球能通过半圆弧最高点P.则小球落地时的动能为5mgR/2D 若小球恰能通过半圆弧最高点P.则小球落地点离D点的水平距离为2R
单选题某教师在讲授《出师表》时，针对文言文难度比较大、篇幅比较长的特点，将课堂导入设计为讲述历史故事“白帝城托孤”，然后引出对课文的讲解。对这一导入环节的设置，评价恰当的是（）。A导入内容偏离了课文主题.不能达到教学目的B运用相关历史故事导入，既激发了学生的学习兴趣，又能将学生的注意力集中到所学知识上C导入形式单一且没有互动.没有让全体学生都参与到教学活动的各个环节中D导入环节没有调动起学生的积极性.不能引起学生的关注和思考
单选题请阅读 Passage 2，完成第 26~30小题。Passage 2 The common cold is the world's most widespread illness， which is plague that flesh receives.The most widespread fallacy of all is that colds caused by cold.They are not， They are caused by viruses passing on from person to person.You catch a cold by coming into contact， directly or indirectly， with someone who already has one.If cold causes colds， it would be reasonable to expect the Eskimos to suffer from them forever.But they do not.And in isolated arctic regions explorers have reported being free from colds until coming into contact again with infected people from the outside world by way of packages and mail dropped from airplanes.During the First World War soldiers who spent long periods in the trenches， cold and wet，showed no increased tendency to catch colds.In the Second World War prisoners at the notorious Auschwitz concentration camp， naked and starving， were astonished to find that they seldom had colds.At the Common Cold Research Unit in England， volunteers took part in Experiments in which they gave themselves to the discomforts of being cold and wet for long stretches of time.After taking hot baths， they put on bathing suits， allowed themselves to be with cold water， and then stood about dripping wet in drafty room.Some wore wet socks all day while others exercised in the rain until close to exhaustion.Not one of the volunteers came down with a cold unless a cold virus was actually dropped in his nose.If， then， cold and wet have nothing to do with catching colds， why are they more frequent in the winter? Despite the most pains-taking research， no one has yet found the answer， One explanation offered by scientists is that people tend to stay together indoors more in cold weather than at other times， and this makes it easier for cold viruses to be passed on.No one has yet found a cure for the cold.There are drugs and pain suppressors such as aspirin， but all they do is relieve the symptoms.The author cites the Eskimos not suffering from common colds forever to indicate ____.Acommon colds are more severe than other plaguesBviruses are the factors causing common coldsCcommon colds are full of mythDthe idea that cold leads to colds doesn’t stand up
单选题They have left New York _____ good; they’ll never go back and live there again.AforBatCbyDin
问答题《杵歌》一课中，教师组织一部分学生跳“杵舞”，另外几名学生把竹竿竖起来当作竹乐器按照一定节奏敲打，为舞者伴奏。学生“玩儿”兴正浓时，“竹乐器”突然向下倒去，学生顿时慌了神，手忙脚乱地欲挽救残局，试图将竹乐器扶起，结果适得其反。教师看见却没能及时制止，导致舞蹈的同学与敲击节奏的同学没有跟上节拍，致使课堂混乱。请对这位教师的教学行为做出评价。
单选题Which of the following is NOT a design feature of human language? _____AArbitrarinessBDisplacementCDualityDDiachronicity