Read the following passage on commuting, and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 51 to 60.
A. They eliminate dead cells
B. They heal wounds
C. They fight bacteria
D. They cause blood clots
* Đáp án
* Hướng dẫn giải
Đáp án là D. They cause blood clots - Chúng làm máu đông.