题干

家蝇对拟除虫菊酯类杀虫剂产生抗性,原因是神经细胞膜上某通道蛋白中的一个亮氨酸替换为苯丙氨酸。下表是对某市不同地区家蝇种群的敏感性和抗性基因型频率调查分析的结果。下列叙述正确的是(   )


A:上述通道蛋白中氨基酸的改变是基因碱基对缺失的结果

B:甲地区家蝇种群中抗性基因频率为22%

C:比较三地区抗性基因频率可知乙地区抗性基因突变率最高

D:丙地区敏感性基因频率高是自然选择的结果

上一题 下一题 0.0难度 选择题 更新时间:2018-04-18 12:01:24

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D

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    Why do Americans struggle with watching their weight, while the French, who consume(消耗) rich food, continue to stay thin? Now a research by Cornell University suggests how life style and decisions about eating may affect weight. Researchers concluded that the French tend to(往往,倾向于) stop eating when they feel full. However, Americans tend to stop when their plate is empty or their favorite TV show is over.

    According to Dr. Joseph Mercola, a health expert, the French see eating as an important part of their life style. They enjoy food and therefore spend a fairly long time at the table, while Americans see eating as something to be squeezed(挤出) between the other daily activities. Mercola believes Americans lose the ability to sense when they are actually full. So they keep eating long after the French would have stopped. In addition, he points out that Americans drive to huge supermarkets to buy canned and frozen foods for the week. The French, instead, tend to shop daily, walking to small shops and farmers' markets where they have a choice of fresh fruits, vegetables, and eggs as well as high-quality meats for each meal.

    After a visit to the United States, Mireille Guiliano, author of French Women Don't Get Fat, decided to write about the importance of knowing when to stop rather than suggesting how to avoid food. Today she continues to stay slim and rarely goes to the gym.

    In spite of(尽管) all these differences, evidence shows that recent life style changes may be affecting French eating habits. Today the rate of obesity — or extreme overweight — among adults is only 6%. However, as American fast food gains acceptance and the young reject(拒绝) older traditions, the obesity rate among French children has reached 17% — and is growing.

同类题3

阅读下文,回答问题

帽子

【波兰】格罗津斯卡

(A)剧院大厅。乐队演奏序曲。

坐在十排的一位先生:对不起,女士!(更大声地)对不起,女士!

坐在九排的女士:干什么?我又不认识你。

十排的先生:您戴着帽子。

九排的女士:我知道自己戴着帽子。

十排的先生:可我一会儿就会什么也看不见了。女士,您能不能把帽子摘了?

九排的女士:很遗憾,不能。

(B)演出开始了。

十排的先生:女士,我可要忍受不了啦,买了票,却什么也看不见。

九排的女士:那你去退票好了。

十排的先生:就因为您不想摘掉这顶高帽子?

九排的女士:现在,除了偏远地区,谁还戴那种趴趴帽。

十排的先生:那么,您能不能把头稍微偏一偏?

九排的女士:好吧!

十排的另一位先生:女士,请您不要歪脑袋,您挡住我了。

九排的女士:是后边的那位先生叫我往这边偏的。他能看见,可你又看不见了,自私自利!

十排的第二位先生:怎么?是你叫这位女士往这边偏的,好让我什么也看不成?

十排的第一位先生:你看不见关我什么事,你站起来不就看见了!

后排的女士:先生,请您坐下!我什么也看不见了。

十排的第二位先生:可坐在我前面的这位女士……

后排的女士:那位女士跟我有什么相干的,您坐下不就完了!

九排的女士:就是嘛!自己站起来,心满意足了,可把别人都挡住了,自私自利!

后排的女士:可不是!请您坐下。

后排的先生:请安静!台上说什么全听不见。

后排的女士:前面这位先生老是站起来,我什么也看不见。

十排的先生:都是这位女士戴着帽子。

后排的先生:请安静!不然我就叫人把你请出去。

九排的女士:就是的!他谁都妨碍,自私自利!

众人:(C)谁在捣乱?

什么也听不见!

你是第一次进剧院还是怎么的?

你喝醉了还是怎么的?

安静!

请你出去!

十排的先生:可是……

九排的女士:好了,好了!如果你安静地坐着,还可以留下。(面向众人)请大家允许他留下吧!

十排的先生:谢谢您,女士!

(选自《世界微型小说经典》百花洲文艺出版社,有删改)