7．基因型为Aa的动物体产生的雌雄配子的数量是
A．雌配子：雄配子=1：1 B．雄配子(A)：雌配子(a)=1：1
C．雄配子：雌配子=3：l D．雄配子比雌配子多
6．基因型为AAbbCC与aaBBcc的小麦进行杂交，这三对等位基因分别位于非同源染色体上，F1杂种形成的配子种类数和F2的基因型种类数分别是
A．4和9 B．4和27 C．8和27 D．32和81
5．下列有关推理不正确的是
A．隐性性状的个体是纯合子
B．隐性个体的显性亲本必为杂合子
C．显性个体的基因型难以独立确定
D．后代全为显性个体，则双亲必为显性纯合子
4．一匹家系不明的雄性黑马与若干匹红马杂交，生出了20匹红马和22匹黑马，你认为亲本这两种马的基因型特点是
A．黑马为显性纯合，红马为隐性纯合 B．黑马为杂合，红马为显性纯合
C．黑马为隐性纯合，红马为显性纯合 D．黑马为杂合，红马为隐性纯合
3．一般人对苯硫脲感觉味苦，由基因B控制，也有人对其无味觉，叫味盲，由基因b控制。若三对夫妇的子女味盲各是25%、50%和100%。则这三对夫妇的基因型最大可能是
①BBXBB ②bbxbb ③BBXbb ④Bb×Bb ⑤Bb×bb ⑥BB×Bb
A．①②③ B．④⑤⑥ C．④②⑤ D．④⑤②
2．下列各杂交组合的所有后代中，与双亲具有相同表现型的是
A．BbSsXbbss B．BbSs×bbSs C．BbSS~BBSs D．BBSs×bbss
1．基因型为AA的牛与杂种公牛表现有角，杂种母牛与基因型为aa的牛表现为无角，现在一对有角牛交配，生下一只无角牛，这只小牛的性别是
A．雄牛 B．雌牛 C．雌、雄牛都可 D．无法确定
8.(★★★★★)In this passage the author mainly discusses ________.
A.how Western school systems mirror the value of individualism
B.the advantages and disadvantages of the two educational systems
C.what Asian schools should do to make students more creative
D.the differences in culture, religion, etc. between the East and West
7.(★★★★★)The main purpose of the passage is to ________.
A.list today’s standards of some food and nutrition
B.introduce what should be eaten and what not
C.explain what is helpful to your health and what is not
D.test our nutrition IQ by judging the problems listed
H
In a society such as the United States or Canada, which has many national, religious and cultural differences, people highly value individualism-the differences among people. Teachers place a lot of importance on the qualities that make each student special. The educational systems in these countries show these values. Students do not memorize information. Instead, they work on their own and find answers themselves. There is often discussion in the classroom. At an early age, students learn to form their own ideas and opinions.
In most Asian societies, by contrast, the people have the same language, history and culture. Perhaps for this reason, the educational system in these Asian countries reflects society’s belief in group goals and purposes rather than individualism. Children in China, Japan, and Korea often work together and help one another on assignments(作业).
There are advantages and disadvantages to both of these systems of education. For example, one advantage to the system in Japan is that students there learn much more math and science than American students learn by the end of high school. They also study more hours each day and more days each year than North Americans do. The system is difficult, but it prepares students for a society that values discipline(纪律)and self-control.There is,however, a disadvantage. Memorization is an important learning method in Japanese schools, yet many students say that after an exam, they forget much of the information that they have memorized.
The advantage of the educational system in North America, on the other hand, is that students learn to think for themselves. The system prepares them for a society that values creative ideas. There is, however, a disadvantage. When students graduate from high school, they haven’t memorized as many basic rules and facts as students in other countries have.
7.Food grown in poor soil is lower in vitamins than food grown in rich soil.
False.The vitamins in our foods are made by the plants themselves.They don’t come from the soil.However,the minerals in a plant depend on the minerals in the soil.
If you have answered these questions correctly,you can say you know much about food and nutrition by today’s standards.But remember that nutrition is growing science and that it may be aged as new information is obtained.