Trong một phép lai phân tích cây quả tròn, hoa vàng, thu được F1 gồm 42 cây quả tròn, hoa vàng : 108 cây quả tròn, hoa trắng : 258 cây quả dài, hoa vàng : 192 cây quả dài, hoa trắng. Biết tính trạng quả do 2 cặp gen Aa, Bb quy định; màu sắc hoa do cặp gen D, d quy định. Kiểu gen của cây quả tròn, hoa vàng đem lai phân tích là

A.  A a B d b D

B.  A b a B D d

C.  A a B D b d

D.  A B D a b d

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions

The custom of paying a bride price before marriage is still a well-established part of many African cultures. In paying a bride price, the family of the groom must provide payment to the family of the bride before the marriage is allowed. The bride price can vary greatly from culture to culture in Africa. In the Zulu and Swazi tribes of southern Africa, the bride price often takes the form of cattle. In Western African, kola nuts, shells, and other goods are often used for the payment of the bride price. The actual payment of money sometimes takes place, but the payment of goods is more frequent. The amount of paid in a bride price can also vary. In modern times, the bride price is occasionally quite small and its value is mainly symbolic. However, the bride price can still be quite high, especially among prominent or highly traditional families.

There are a number of justifications used to explain the payment of bride price. The first is that the bride price represents an acknowledgement of the expense the bride’s family has gone in order to raise her and bring her up as a suitable bride for the groom. It also represents payment for the loss of a family member, since the bride will officially become a member of her husband’s family and will leave her own. On a deeper level the bride price represents payment for the fact that the bride will bring children into the family of the groom, thereby increasing the wealth of the family. This concept is reinforced by the fact that the bride price must often be returned if the bride fails to bear children.

The payment of the bride price has quite a number of effects on African society. First, the payment of bride price acts to increase the stability of African family structures. Sons are dependent on their fathers and older relatives to help them pay the bride price of their wives, and this generally leads to greater levels of obedience and respect. The negotiations between the two families concerning the bride price allow the parents and other family members to meet and get to know one another before the marriage. Finally, since the bride price must often be repaid in case of divorce, the bride’s family often works to make sure that any marital problems are solved quickly. Bride prices also work as a system of wealth distribution in African cultures. Wealthier families can afford to support the marriage of their son, and thus their wealth is transferred to other families.

Which of the sentences below best expresses the essential information in the underlined sentence in the passage?

A. obedient and respectful sons can rely on their fathers and elder to help them pay the bride price of their wives

B. sons are dependent on their fathers and elders, and this makes them more obedient and respectful

C. sons respect the fact that their fathers and elders will help them pay the bride price of their wives

D. young men must obey their father and elders because they need their help to pay the bride price of the their wives

Tính khối lượng anilin có trong dung dịch A biết rằng khi cho tác dụng vào nước brom thì thu được 6,6 gam kết tủa trắng. Giả sử hiệu suất của cả hai trường hợp là 100%.

Cho 9,36 gam hỗn hợp gồm 3 amino axit (phân tử chỉ chứa một nhóm cacboxyl và một nhóm amino) vào dung dịch chứa 0,1 mol axit malonic, thu được dung dịch X. Thêm tiếp 400 ml dung dịch KOH 1M vào dung dịch X, sau khi các phản ứng xảy ra hoàn toàn, cô cạn dung dịch sau phản ứng thu được 36,76 gam chất rắn khan Y. Hòa tan Y trong dung dịch HCl dư, thu được dung dịch chứa m gam muối. Giá trị của m là:

A. 46,46

B. 42,81

C. 39,16

D. 13,01

Đun nóng m gam hỗn hợp X gồm các chất có cùng một loại nhóm chức với 720 ml dung dịch NaOH 1,15M, thu được dung dịch Y chứa muối của một axit cacboxylic đơn chức và 18,48 gam hơi Z gồm các ancol. Cho toàn bộ Z tác dụng với Na dư, thu được 6,048 lít khí H₂ (đktc). Cô cạn dung dịch Y, nung nóng chất rắn thu được với CaO cho đến khi phản ứng xảy ra hoàn toàn, thu được 8,64 gam một chất khí. Giá trị của m gần nhất với

A. 40,8.

B. 41,4.

C. 27.

D. 48,6.

Dựa vào bảng 6.3, vẽ biểu đồ so sánh GDP của Hoa Kì với thế giới và một số châu lục.

BẢNG 6.3. GDP CỦA HOA KÌ VÀ MỘT SỐ CHÂU LỤC - NĂM 2004

(Đơn vị: tỉ USD)

Có thể đo được chiều rộng của một khúc sông mà không cần phải sang bờ bên kia hay không?

Người ta tiến hành đo đạc các yếu tố hình học cần thiết để tính chiều rộng của khúc sông mà không cần phải sang bờ bên kia. Nhìn hình vẽ đã cho, hãy mô tả những công việc cần làm và tính khoảng cách AB =x theo BC =a, B’C’ = a’; BB’ = h.

Read the following passage on transport, and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 43 to 50.

1) It was the first photograph that I had ever seen, and it fascinated me. I can remember holding it at every angle in order to catch the flickering light from the oil lamp on the dresser. The man in the photograph was unsmiling, but his eyes were kind. I had never met him, but I felt that I knew him. One evening when I was looking at the photograph, as I always did before I went to sleep, I noticed a shadow across the man’s thin face. I moved the photograph so that the shadow lay perfectly around his hollow cheecks. How different he looked!

(2) That night I could not sleep, thinking about the letter that I would write. First, I would tell him that I was eleven years old, and that if he had a little girl my age, she could write to me instead of him. I knew that he was a very busy man. Then I would explain to him the real purpose of my letter. I would tell him how wonderful he looked with the shadow that I had seen across his photograph, and I would most carefully suggest that he grow whiskers.

(3) Four months later when I met him at the train station near my home in Westfield, New York, he was wearing a full beard. He was so much taller than I had imagined from my tiny photograph.

(4) “Ladies and gentlemen,” he said, “I have no speech to make and no time to make it in. I appear before you that I may see you and that you may see me.” Then he picked me right up and kissed me on both cheeks. The whiskers scratched. “Do you think I look better, my little friend?” he asked me.

(5) My name is Grace Bedell, and the man in the photograph was Abraham Lincoln. 

Why did the author wait until the last line to reveal the identity of the man in the photograph?

A. The author did not know it. 

B. The author wanted to make the reader fell foolish. 

C. The author wanted to build the interest and curiosity of the reader. 

D. The author was just a little girl.

Người đàn ông nhóm máu A ở một quần thể cân bằng di truyền có tỉ lệ người mang nhóm máu O là 4% và nhóm máu B là 21 %. Kết hôn với người phụ nữ có nhóm máu A ở một quần thể cân bằng di truyền khác có tỉ lệ người có nhóm máu O là 9% và nhóm máu A là 27%. Tính xác suất họ sinh được 2 người con khác giới tính, cùng nhóm máu A?

A. 85,73%

B. 46,36% 

C. 43,51% 

D. 36,73%