填空题Questions 1-2 Choose TWO letters A-E. Write your answers in boxes 1-2 on your answer sheet. The list below gives some reasons from the passage. Which TWO of these reasons for ancient mega mammal extinctions are NOT mentioned in the passage 1 ?
A. The significant changes in the Earth's climate
B. The reversion of magnetism of the Earth's poles
C. The emission of some specific gases in the Earth