题干

在豚鼠中,黑色(C)对白色(c)、毛皮粗糙(R)对毛皮光滑(r)是显性。能验证基因的自由组合定律的最佳杂交组合是(  )

A:黑光×白光→18黑光∶16白光

B:黑光×白粗→25黑粗

C:黑粗×白粗→15黑粗∶7黑光∶16白粗∶3白光

D:黑粗×白光→10黑粗∶9黑光∶10白粗∶11白光

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答案(点此获取答案解析)

D

同类题2

阅读理解

    "Listen carefully to what I say,"  the time traveler said, "I shall tell you something that you will not agree."

    "Why will we not agree?" I asked.

    "Because the science and mathematics you know are not correct," he said. "You believe there are only three dimensions(三维空间)-length, breadth(宽) and thickness."

    "There is nothing to argue with that, "  the youngest member of our little group said.

    "Exactly!"  the time traveler answered, "But there is also a fourth dimension - time."

    "We all know about time, " another member of the group said. "Time passed."

    "I do not agree,"  the time traveler said, "Length, breadth and thickness do not pass. They stay in the same place in space.  We move about them. I can prove that time is the same. It does not pass. We move in time the same way that we move in breadth, length and thickness."

    None of us believed the time traveler, and we argued with him for many hours.

    "If we could travel back in time,"  the scientist said, "We could do things to change the future."

    "If we could travel forward in time," the doctor(博士) said, "we could do things that change our present."

    The time traveler smiled, "It is clear," he said, "that there is only one way I can show you that I am right. We must do an experiment. Please wait here."

    He left the room and soon returned, carrying what looked like a clock.

    "This is a model of a time machine. It took me two years to make it," the time traveler said. "I want all of you to understand that when I start the machine, it will immediately travel in time and disappear from the present."

    He turned to the youngest of all. "Give me your hand," he said.

    The young man put out his hand. The time traveler took it and placed it on the machine. Immediately, there was a sudden wind, and the little machine disappeared.

    I was certain this was not a trick, but the doctor was not so sure.

    "Are you asking us to believe," he said, "that the machine is now in a different time?"

    "Certainly! In my laboratory, a full-size machine is almost complete. As soon as it is complete, I shall send myself on a journey through time. Would you like to see my machine?"

    "Are you serious about this?" the doctor asked.

    "I have never been more serious about anything," the time traveler said, "Come."

    We followed him to his laboratory. There, we saw the actual machine, not quite complete, but large enough for a man to sit in.

同类题3

阅读下面的文字,完成下面小题。

明星畸高片酬谁之过

詹庆生

    ①近段时间,影视明星高片酬的话题引发了舆论热议。其实,明星超高片酬对影视行业健康发展的危害早已被广泛论及:占投资成本过半甚至更高比例的演员片酬,挤占了制作其他环节的成本投入,严重影响了影视作品的艺术质量;对明星片酬的无节制哄抬,对影视行业的健康发展造成威胁;随之而来的影视演员一夜暴富、拜金炫富等现象所传达的价值观偏差,也给社会精神文化建设带来很大冲击。

    ②在影视产业高速发展的背景下,制片、发行、放映的全产业链都进入了急剧扩张期。仅就制片领域来说,各种热钱汹涌而至。而在放映播映平台方面,也猛增许多。这些新出现的影视投资、制片、发行、放映主体为中国影视业创造的“世界奇迹”贡献巨大。然而,当其他环节都在急剧扩张的时候,有市场号召力的明星却难在短时间内出现数量的快速增长。价格是由供需关系决定的,当市场需求急剧扩张而供给相对不足时,作为“稀缺资源”的明星价格上涨似乎就成了必然。

    ③近两年来,各影视公司不仅给明星开出超高片酬,还纷纷高价收购明星们的公司以期绑定与明星之间的合作关系。更为雪上加霜的是,许多刚刚进入影视制片领域的新军,为了在激烈的明星资源争夺战中占得先机,往往打破既有的行业规则,为明星开出难以拒绝的超高片酬。

    ④事实上,成熟的影视工业体系对于明星的依赖并没有那么强,创意和制作才是最为重要的。以好莱坞为例,一些风靡全球的影视作品,启用的大多是小演员甚至是名不见经传的新演员。这些作品的成功并不依赖明星的光环,而是富有想象力的故事创意、生动精湛的演技,以及令人瞠目结舌的制作水平。反倒是这些作品成就和培养了一批演员,让他们走上明星之路。而在稳定的影视工业体系当中,影视公司、演员、经纪公司之间已经形成了相对稳定的谈判议价的行业规则,明星片酬固然会因走红程度而起伏,但并没有出现类似中国这样片酬大面积坐地飙升的反常情况。所以,当前中国影视业中明星片酬反常飙升、过度依赖明星的畸形现象,恰恰折射出了当前中国影视产业在创意能力、制作水准、工业化水平等方面均未发展成熟的现实。“唯票房论”使中国影视产业处于前所未有的浮躁时期,那些蜂拥而入的热钱更是以赚快钱为目标,导致急功近利的思维方式弥漫整个影视业,IP热追IP,“鲜肉”热追“鲜肉”,明星似乎成了赢利的保证,而故事创意、表演艺术、精良制作这些对于影视生产至关重要的环节,反倒成了可以忽略不计的东西。在经历了前几年的疯狂之后,电影市场今年第二季度以来包括暑期档的低迷现象,已经给那些故事拙劣、面瘫表演、制作粗糙、批量出炉的影片以冷酷的回应。虚火上升的市场终将面临现实的惩罚。

    ⑤可以说,反常的规模化高片酬现象,固然有基于供需关系失衡的市场原因,但归根结底,还是处于粗放式增长模式中的中国影视产业结出的病态畸形的恶果,是狂飙突进背景下的产业“热症”,与远不成熟的产业“幼稚病”双症并发的典型症候。找到病根才能对症下药。对于反常高片酬、追捧明星的现象,我们应该以倡导行业自律,加强行业规范,对于节目形态和导向进行宏观引导,在产品购播与营销环节加强政策指导和舆论管控来治标,再以加快中国影视产业的整体升级,建立成熟规范的现代影视工业体系来治本。

(选自《光明日报》2016年10月)