Question

[Lê Quỳnh Anh]

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.

According to paragraph 2, evidence from fossil suggests that

A. extinction of species has occurred from time to time throughout Earth’s history

B. dinosaurs became extinct much earlier than scientists originally believed

C. extinctions on Earth have generally been massive

D. there has been only one mass extinction in Earth’s history

Answer 1

[Dương Hoàn Anh]

Đáp án A

Theo đoạn 2, bằng chứng từ hóa thạch chỉ ra rằng:

A. Sự tuyệt chủng của các loài đã xảy ra liên tục trong suốt tiến trình lịch sử Trái Đất.

B. Khủng long đã tuyệt chủng sớm hơn nhiều so với các nhà khoa học tin rằng.

C. Sự tuyệt chủng trên trái đất nhìn chung là mang tính hàng loạt.

D. Chỉ có duy nhất 1 lần sự tuyệt chủng hàng loạt diễn ra trong lịch sử Trái Đất.

Dẫn chứng ở câu đầu tiên đoạn 2: “The fossil record reveals that extinction has occurred throughout the history of Earth”- ( Ghi nhận về hóa thạch tiết lộ rằng sự tuyệt chủng đã xảy ra trong suốt tiến trình lịch sử Trái Đất)