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According to the passage, scientists used isotopes from...

Câu hỏi: 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 from 35 to 42
Scientists have discovered that for the last 160,000 years, at least, there has been a consistent relationship between the amount of carbon dioxide in the air and the average temperature of the planet. The importance of carbon dioxide in regulating the Earth's temperature was confirmed by scientists working in eastern Antarctica. Drilling down into a glacier, they extracted a mile-long cylinder of ice from the hole. The glacier had formed as layer upon layer of snow accumulated year after year. Thus, drilling into the ice was tantamount to drilling back through time.
The deepest sections of the core are composed of water that fell as snow 160,000 years ago. Scientists in Grenoble, France, fractured portions of the core and measured the composition of ancient air released from bubbles in the ice. Instruments were used to measure the ratio of certain isotopes in the frozen water to get an idea of the prevailing atmospheric temperature at the time when that particular bit of water became locked in the glacier.
The result is a remarkable unbroken record of temperature and of atmospheric levels of carbon dioxide. Almost every time the chill of an ice age descended on the planet, carbon dioxide levels dropped. When the global temperature dropped 9°F (5°C), carbon dioxide levels dropped to 190 parts per million or so. Generally, as each ice age ended and the Earth basked in a warm interglacial period, carbon dioxide levels were around 280 parts per million. Through the 160,000 years of that ice record, the level of carbon dioxide in the atmosphere fluctuated between 190 and 280 parts per million, but never rose much higher until the Industrial Revolution beginning in the eighteenth century and continuing today.
There is indirect evidence that the link between carbon dioxide levels and global temperature change goes back much further than the glacial record. Carbon dioxide levels may have been much greater than the current concentration during the Carboniferous period, 360 to 285 million years ago. The period was named for a profusion of plant life whose buried remains produced a large fraction of the coal deposits that are being brought to the surface and burned today.
According to the passage, scientists used isotopes from the water of the ice core to determine which of following?
A. The amount of air that had bubbled to the surface since the ice had formed
B. The temperature of the atmosphere when the ice was formed
C. The date at which water had become locked in the glacier
D. The rate at which water had been frozen in the glacier
Kỹ năng: Đọc
Giải thích:
Theo đoạn văn, các nhà khoa họ sử dụng chất đồng vị từ nước trong lõi đá để xác định cái gì:
Lượng không khí đã nổi bọt lên tới bề mặt kể từ khi đá hình thành
Nhiệt độ khí quyển khi đá được hình thành
Ngày mà nước bị giữ trong sông băng
Tốc độ nước bị đóng băng trong sông băng
Đáp án: B. Giải thích: Thông tin nằm ở:
"Instruments were used to measure the ratio of certain isotopes in the frozen water to get an idea of the prevailing atmospheric temperature at the time when that particular bit of water became locked in the glacier." (Các công cụ đã được sử dụng để đo tỷ lệ của các đồng vị nhất định trong nước đóng băng để xác định nhiệt độ khí quyển phổ biến tại thời điểm khi một lượng nước đặc biệt đó bị khóa trong sông băng.)
Đáp án B.