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 ...
Đặng Bảo Trâm | Chat Online | |
04/09 18:17:47 (Tiếng Anh - Lớp 12) |
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 the passage, it is believed that the largest extinction of a species occurred
Lựa chọn một trả lời để xem Đáp án chính xác Báo sai đáp án hoặc câu hỏi |
A. 250 million years ago 0 % | 0 phiếu |
B. 225 million years ago 0 % | 0 phiếu |
C. 65 million years ago 0 % | 0 phiếu |
D. 26 million years ago 0 % | 0 phiếu |
Tổng cộng: | 0 trả lời |
Trắc nghiệm liên quan
- 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 ... (Tiếng Anh - Lớp 12)
- 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 ... (Tiếng Anh - Lớp 12)
- 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 ... (Tiếng Anh - Lớp 12)
- 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 ... (Tiếng Anh - Lớp 12)
- 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 ... (Tiếng Anh - Lớp 12)
- 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 ... (Tiếng Anh - Lớp 12)
- Mark the letter a, B, C, or D on your answer sheet to choose the best option for each numbered gap to complete the following passage from 1 to 5. Many thousands of children have …. (1).….in their homes. As a result, some children died. The most ... (Tiếng Anh - Lớp 12)
- Mark the letter a, B, C, or D on your answer sheet to choose the best option for each numbered gap to complete the following passage from 1 to 5. Many thousands of children have …. (1).….in their homes. As a result, some children died. The most ... (Tiếng Anh - Lớp 12)
- Mark the letter a, B, C, or D on your answer sheet to choose the best option for each numbered gap to complete the following passage from 1 to 5. Many thousands of children have …. (1).….in their homes. As a result, some children died. The most ... (Tiếng Anh - Lớp 12)
- Mark the letter a, B, C, or D on your answer sheet to choose the best option for each numbered gap to complete the following passage from 1 to 5. Many thousands of children have …. (1).….in their homes. As a result, some children died. The most ... (Tiếng Anh - Lớp 12)
Trắc nghiệm mới nhất
- Tính đến năm 2020, Liên hợp quốc có bao nhiêu thành viên? (Địa lý - Lớp 11)
- Một khối gỗ hình hộp chữ nhật có các kích thước dài 10 cm, rộng 5 cm và chiều cao 4 cm. Đặt khối gỗ trên bàn theo cách nào thì áp suất gây ra trên bàn nhỏ nhất? (Khoa học tự nhiên - Lớp 8)
- Khối lượng nước trong ống đong được tính theo công thức (Khoa học tự nhiên - Lớp 8)
- Việt Nam là thành viên của các tổ chức liên kết khu vực nào sau đây? (Địa lý - Lớp 11)
- Điền vào chỗ trống: "Khi biết khối lượng riêng của một vật, ta có thể biết vật đó được cấu tạo bằng chất gì bằng cách đối chiếu với bảng ... của các chất." (Khoa học tự nhiên - Lớp 8)
- Tổ chức liên kết khu vực nào sau đây có sự tham gia của các nước ở nhiều châu lục khác nhau nhất? (Địa lý - Lớp 11)
- Đốt cháy 1,8 g kim loại M, thu được 3,4 g một oxide. Công thức của oxide đó là (Khoa học tự nhiên - Lớp 8)
- Công thức hoá học của potassium hydroxide là (Khoa học tự nhiên - Lớp 8)
- Công thức hoá học của acid có trong dịch vị dạ dày là (Khoa học tự nhiên - Lớp 8)
- Nước muối sinh lí (dung dịch NaCl 0,9%) được sử dụng nhiều trong y học và trong cuộc sống hàng ngày. Để pha chế 500g nước muối sinh lí ta cần: (Khoa học tự nhiên - Lớp 8)