问题 实验题

开始使用杀虫剂时,对某种害虫效果显著,但随着杀虫剂的继续使用,该种害虫表现出越来越强的抗药性。实验说明害虫种群中原来就存在有抗药性的个体,这证明:

(1)害虫种群中不同个体间存在着     ,体现了生物的变异一般是     的。

(2)杀虫剂对害虫起了     作用,而这种作用是     的。

(3)害虫抗药性增强,是通过害虫与杀虫剂之间的     来实现的。

答案

(1)差异;不定向;(2)选择;定向;)(3)生存斗争.

题目分析::(1)首先害虫存在两种变异品种:抗药能力强的害虫与抗药能力差的害虫.农药使害虫中抗药能力差的害虫死亡,而抗药能力强的害虫活了下来.害虫种群中存在着差异,体现了生物的变异一般是不定向的.(2)生物界普遍存在变异,每一代都存在变异,没有两个生物个体是完全相同的,变异是随机产生的;这些变异都是由遗传物质决定的,是可遗传的变异;这样控制抗药能力强的基因得到积累与加强,使用时间越长,效果越差.说明杀虫剂对害虫起了选择作用,而这种作用是定向的.(3)达尔文认为,在生存斗争中,具有有利变异的个体,容易在生存斗争中获胜而生存下去.反之,具有不利变异的个体,则容易在生存斗争中失败而死亡;害虫的有些变异具有抗药性,在生存斗争中获胜而被保留下来,从而产生了抗药性的害虫;在这个过程中害虫抗药性增强,是通过害虫与杀虫剂之间的生存斗争来实现的.故答案为:(1)差异;不定向;(2)选择;定向;)(3)生存斗争.

选择题
阅读理解

E

"Opinion" is a word that is used carelessly today. It is used to refer to matters of taste, belief, and judgment. This casual use would probably cause little confusion if people didn’t attach too much importance to opinion. Unfortunately, most do attach great importance to it. "I have as much right to my opinion as you to yours, '' and ''Everyone’s entitled(授予…权利) to his opinion, '' are common expressions. In fact, anyone who would challenge another's opinion is likely to be branded intolerant.

Is that label(标签)accurate? Is it intolerant to challenge another's opinion? It depends on what definition of opinion you have in mind. For example, you may ask a friend ''What do you think of the new Ford cars?" And he may reply, "In my opinion, they're ugly." In this case, it would not only be intolerant to challenge his statement, but foolish. For it's obvious that by opinion he means his personal preference, a matter of taste. And as the old saying goes, ''It's pointless to argue about matters of taste."

But consider this very different use of the term, A newspaper reports that the Supreme Court has delivered its opinion in a controversial case. Obviously the justices did not state their personal preferences, their mere likes and dislikes. They stated their considered judgment, painstakingly arrived at after thorough inquiry and careful consideration.

Most of what is referred to as opinion falls somewhere between these two extremes. It is not an expression of taste. Nor is it careful judgment. Yet it may contain elements of both. It is a view or belief more or less casually arrived at, with or without examining the evidence.

 Is everyone entitled to his opinion? Of course, this is not only permitted, but guaranteed. We are free to act on our opinions only so long as, in doing so, we do not harm others.

72. Which of the following statements is TRUE, according to the author?

A. Everyone has a right to hold his own opinion.

B. Free expression of opinions often leads to confusion.

C. Most people tend to be careless in forming their opinions.

D. Casual use of the word "opinion" often brings about quarrels.

73. According to the author, who of the following would be labelled as intolerant?

A. Someone who turns a deaf ear to others' opinions.

B. Someone who can't put up with others' tastes.

C. Someone who values only their own opinions.

D. Someone whose opinion harms other people.

74. The new Ford cars are mentioned as an example to show that ________.

A. it is foolish to criticize a famous brand

B. one should not always agree to others' opinions

C. personal tastes are not something to be challenged

D. it is unwise to express one's likes and dislikes in public

75. Considered judgment is different from personal preference in that ________.

A. it is stated by judges in the court

B. it reflects public like and dislikes

C. it is a result of a lot of controversy (争论,争议)

D. it is based on careful thought