Đậu Hà Lan có bộ nhiễm sắc thể lưỡng bội 2n=14. Tế bào sinh dưỡng của thể ba thuộc loài này có bao nhiêu nhiễm sắc thể?

A. 13

B. 15

C. 21

D. 42

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 25 to 29. Fill in the appropriate word in question 27

  Nowadays people are more aware that wildlife all over the world is in danger. Many species of animals will become (25) _________ if we do not make an effort to protect them. There are many reasons for this. In some cases, animals are (26) _________ for their fur or for other valuable parts of their bodies.

  Some birds, such as parrots, are caught alive and sold as pets. For many animals and birds the problem is that their habitat - the place where they live - is (27)_________. More land is used for farms, for houses

or industry, and there are fewer open spaces than there once were. Farmers use powerful chemicals to help them grow better crops, but these chemicals pollute the environment and (28)  _________wildlife. The most successful animals on earth - human beings - will soon be the only ones (29) _________, unless we can solve this problem.

A. escaping

B. departing

C. exhausting

D. disappearing

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 25 to 29. Fill in the appropriate word in question 25

  Nowadays people are more aware that wildlife all over the world is in danger. Many species of animals will become (25) _________ if we do not make an effort to protect them. There are many reasons for this. In some cases, animals are (26) _________ for their fur or for other valuable parts of their bodies.

  Some birds, such as parrots, are caught alive and sold as pets. For many animals and birds the problem is that their habitat - the place where they live - is (27)_________. More land is used for farms, for houses

or industry, and there are fewer open spaces than there once were. Farmers use powerful chemicals to help them grow better crops, but these chemicals pollute the environment and (28)   _________wildlife. The most successful animals on earth - human beings - will soon be the only ones (29) _________, unless we can solve this proble

A. empty

B. vanished

C. disappeared

D. extinct

Mark the letter A, B, C or B on your answer sheet to indicate the correct answer to each of the following questions.

Instead _________petrol, cars will only run _________ solar energy and electricity.

A. of / on

B. for / by

C. in / over

D. from/ upon

Mark the letter A, B, C or B on your answer sheet to indicate the correct answer to each of the following questions.

Most doctors and nurses have to work on a _________ once or twice a week at the hospital.

A. solution

B. night shift

C. household chores

D. special dishes

Mark the letter A, B, C or B on your answer sheet to indicate the correct answer to each of the following questions.

I come from a city _________ is located in the southern part of the country.

A. who

B. whom

C. that

D. whose

Mark the letter A, B, C or B on your answer sheet to indicate the correct answer to each of the following questions.

An international medical conference initiated by Davison resulted in the birth of the League of Red Cross Societies in 1991.

A. started

B. helped

C. treated

D. dedicated

Mark the letter A, B, C or D on your answer sheet to indicate the word(s)  OPPOSITE in meaning to the underlined word(s) in each of the following questions.

There is growing concern about the way man has destroyed the environment.

A. ease

B. speculation

C. consideration

D. attraction

Mark the letter A, B, C or D on your answer sheet to indicate the most suitable response to complete each of the following exchanges.

“I’d like to take four weeks” holiday”. “ ...............We have too much work to do.

A. Forget it

B. Pardon me 

C. Don’t worry

D. Don’t mention it

Tổng số hợp chất hữu cơ no, đơn chức, mạch hở, có cùng công thức phân tử C₅H₁₀O₂, phản ứng được với dung dịch NaOH nhưng không có phản ứng tráng bạc là

A. 4

B. 5

C. 8

D. 9