The author mentions the extinction of the dinosaur...

Câu hỏi: The author mentions the extinction of the dinosaurs in the 2nd paragraph to emphasize that                      .  

A the cause of the dinosaurs’ extinction is unknown

B actions by humans could not stop the irreversible process of a species’ extinction

C not all mass extinctions have been caused by human activity

D Earth’s climate has changed significantly since the dinosaurs’extinction