Question

Mark the letter a, B, C, or D on your answer sheet to indicate the sentence that is closest meaning to each of the following questions or indicate the correct answer to each of them from 1 to 7

It is estimated that over 99 percent of all species that ever existed have become extinct. What causes extinction? When a species is no longer adapted to a changed environment, it may perish. The exact causes of a species’ death vary from situation to situation. Rapid ecological change may render an environment hostile to a species. For example, temperatures may change and a species may not be able to adapt. Food resources may be affected by environmental changes, which will then cause problems for a species requiring these resources. Other species may become better adapted to an environment, resulting in competition and, ultimately, in the death of a species.

The fossil record reveals that extinction has occurred throughout the history of Earth. Recent analyses have also revealed that on some occasions many species become extinct at the same time- a mass extinction. One of the best- known examples of mass extinction occurred 65 million years ago with the demise of dinosaurs and many other forms of life. Perhaps the largest mass extinction was the one that occurred 225 million years ago, when appropriately 95 percent of all species died. Mass extinction can be caused by a relatively rapid change in the environment and can be worsened by the close interrelationship of many species. If, for example, something were to happen to destroy much of the plankton in the oceans, then the oxygen content of Earth would drop, affection even organisms not living in the ocean. Such a change would probably lead to a mass extinction.

One interesting, and controversial, finding is that extinctions during the past 250 million years have tended to be more intense every 26 million years. This periodic extinction might be due to intersection of the Earth’s orbit with a cloud of comets, but this theory is purely speculative. Some researchers have also speculated that extinction may often be random. That is, certain species may be eliminated and others may survive for no particular reason. A species’ survival may have nothing to do with its ability to adapt. If so, some of evolutionary history may reflect a sequence of essentially random events.

Why is “plankton” mentioned in the second paragraph?

A. To demonstrate the interdependence of different species

B. To illustrate a comparison between organisms that live on the land and those that live in the ocean

C. To emphasize the importance of food resources in preventing mass extinction

D. To point out that certain species could never become extinct

Answer 1

Đáp án A

Tại sao sinh vật phù du được đề cập tới ở đoạn 2?

A. Để chứng minh sự phụ thuộc giữa các loài khác nhau.

B. Để minh họa cho sự so sánh giữa các sinh vật sống trên mặt đất và những sinh vật sống trong đại dương.

C. Để nhấn mạnh tầm quan trọng của nguồn thức ăn trong việc ngăn chặn sự tuyệt chủng hàng loạt.

D. Để chỉ ra rằng một số loài nhất định sẽ không bao giờ bị tuyệt chủng.

Dẫn chứng ở câu thứ 5+6 ở đoạn 2: “ Mass extinction can be caused by a relatively rapid change in the environment and can be worsened by the close interrelationship of many species. If, for example, something were to happen to destroy much of the plankton in the oceans, then the oxygen content of Earth would drop, affection even organisms not living in the ocean” – ( Sự tuyệt chủng hàng loạt bị gây ra bởi sự biến đổi môi trường nhanh chóng và có thể tồi tệ hơn là do mối tương quan mật thiết giữa các loài. Ví dụ như có điều gì đó xảy ra làm hủy diệt số lượng lớn các loài sinh vật phù dù trong đại dương, thì lượng ô-xi trên trái đất cũng từ đó mà giảm theo làm ảnh hưởng không chỉ tới các loài sinh vật đại dương).