问题 填空题 案例分析题

植物在单侧光照射下弯向光源生长。这个现象被解释为“光线能够使生长素在背光一侧比向光一侧分布多”。为什么生长素在背光一侧比向光一侧分布多?是因为向光侧的生长素在光的影响下被分解了,还是向光侧的生长素向背光侧转移了。

为此,有人做了下述实验:A、B、C、D四个完全相同的琼脂块按如图顺序放置在两个相同的胚芽鞘尖端下面,一个有单侧光照,一个无;一段时间后,取出琼脂块分别放置到四个相同的去掉尖端的胚芽鞘的切口的一侧,如图甲、乙、丙、丁。其它条件适宜,一段时间观察去掉尖端的胚芽鞘的弯曲程度。

如果是因为向光侧的生长素在光的影响下被分解了,则胚芽鞘的弯曲程度为()(用数学关系符号来连接甲、乙、丙、丁表示)。

答案

参考答案:甲=乙=丙﹥丁

多选题
单项选择题

Do animals have a culture What do we mean by "culture" Lately social scientists have begun to ask if culture is found just in humans, or if some animals have a culture too. When we speak of culture, we mean a way of life a group of people have in common. Culture includes the beliefs and attitudes we learn. It is the patterns of behavior that help people to live together. It is also the patterns of behavior that make one group of people different from another group.
Our culture lets us make up for having lost out strength, claws, long teeth, and other defenses. Instead we use tools, cooperate with one another, and communicate with language. But these aspects of human behavior, or "culture," can also be found in the lives of certain animals. Animals can make tools, for example. We used to think that the ability to use tools was the dividing line between human beings and other animals. Lately, however, we have found that this is not the case. Chimpanzees(黑猩猩) can not only use tools but actually make tools themselves. Animals can also share knowledge with each other and use their own language to communicate. So it may be important for us to know that the line dividing us from animals is not as clear as we used to think.

The first sentence of the second paragraph "Our culture lets us make up for having lost our strength, claws, long teeth, and other defenses" means ______.

A.as a result of our culture, we have lost our strength, claws, long teeth, and other defenses

B.our culture has enabled us even better though we have lost our strength, claws, long teeth, and other defenses

C.our culture has brought back to us strength, claws, long teeth, and other defenses that we have lost

D.our culture asks that we lose our strength, claws, long teeth, and other defenses which animals still have