Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions:

Life originated in the early seas less than a billion years after the Earth was formed. Yet another three billion years were to pass before the first plants and animals appeared on the continents. Life’s transition from the sea to the land was perhaps as much of an evolutionary challenge as was the genesis of life. What forms of life were able to make such a drastic change in lifestyle? The traditional view of the first terrestrial organisms is based on megafossils-relatively large specimens of essentially whole plants and animals. Vascular plants, related to modern seed plants and ferns, left the first comprehensive megafossil record. Because of this, it has been commonly assumed that the sequence of terrestrialization reflected the evolution of modern terrestrial ecosystems. In this view, primitive vascular plants first colonized the margins of continental waters, followed by animals that feed on the plants, and lastly by animals that preyed on the plant-eaters. Moreover, the megafossils suggest that terrestrial life appeared and diversified explosively near the boundary between the Silurian and the Devonian periods, a little more than 400 million years ago. Recently, however, paleontologists have been taking a closer look at the sediments below this Silurian-Devonian geological boundary. It turns out that some fossils can be extracted from these sediments by putting the rocks in an acid bath. The technique has uncovered new evidence form sediments that were deposited near the shores of the ancient oceans- plant microfossils and microscopic pieces of small animals. In many instances the specimens are less than one-tenth of a millimeter in diameter. Although they were entombed in the rocks for hundreds of millions of years, many of them fossils consist of the organic remains of the organism. These newly discovered fossils have not only revealed the existence of previously unknown organisms, but have also pushed back these dates for the invasion of land by multicellular organisms. Our views about the nature of the early plant and animal communities are now being revised. And with those revisions come new speculations about the first terrestrial life-forms.

Question: What can be inferred from the passage about the fossils mentioned in the third paragraph?         

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Một số câu hỏi khác có thể bạn quan tâm.

• Pha sáng của quang hợp là gì?

• Phát biểu nào sau đây là sai :  

•  Pha tối của quang hợp diễn ra ở đâu?

• Khi tăng dần nhiệt độ, khả năng dẫn điện của hợp kim         

• Điều kiện xảy ra quá trình hô hấp sáng ở thực vật C3 là:

• Các nguyên tố với số hiệu nguyên tử sau: X (Z=1); Y (Z=7); E (Z=12); T (Z=19). Dãy gồm các nguyên tố kim loại là:

•  Chất nhận CO2 đầu tiên ở thực vật C3:

• Cho cấu hình electron nguyên tử (ở trạng thái cơ bản) các nguyên tố như sau: (1) 1s22s22p63s23p64s1                 (2) 1s22s22p63s23p3                 (3)1s22s22p63s23p1           (4) 1s22s22p3                           (5) 1s22s22p63s2 (6) 1s22s22p63s1  Các cấu hình electron không phải của kim loại là:          

• Tính chất vật lí của kim loại không do các electron tự do quyết định là  

• Pha sáng của quang hợp là pha chuyển hóa năng lượng của ánh sáng: