Người ta thu O₂ bằng cách đẩy nước là do tính chất

A. khí oxi tan tốt nước

B. khí oxi khó hoá lỏng

C. khí oxi ít tan  trong nước

D. khí oxi nhẹ hơn nước

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 29

  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. missing

B. over

C. survived

D. left