2020年1月11日托福阅读真题+题目+答案：Three Theories about Origin of Life

2020年1月11日托福阅读真题+题目+答案：Three Theories about Origin of Life

Oxygen and nitrogen are major components of our current atmosphere. But the kinds of hydrogen reactions with other gases that are required to transform simple organic molecules into complex ones are interrupted by oxygen, which combines with hydrogen atoms from other compounds. Therefore, life on Earth must have originated when there was very little oxygen in Earth’s atmosphere. The modern scientific theory of life’s origin was first formulated in the 1920s by Russian scientist Aleksandr Oparin and independentiy by British scientist J. B. S. Haldane. The assumption that life sprang up from chemical reactions that were initiated in the early atmosphere(oxygen-poor/hydrogen-rich) and came to completion in the early oceans was posited by the Oparin-Haldane hypothesis, as it came to be called. Oparin and Haldane suggested that the hydrogen-containing gases caused to react with each other to form organic compounds by energy sources such as sunlight and lightning.

1. By suggesting that he theory of life’s origin was first formulated by Oparin and independently by Haldane, the author means that

(A) haldane planed the theory in greater detail tan Oparin

(B) Oparin devised the theory in cooperation with Haldane

(C) haldane formulated the theory separately from Oparin

(D) Oparin developed the theory much earlier than Haldane

With regard to the view that these complex organic compounds could have begun to shape in Earth’s oceans, some researchers remain skeptical. The probability that the fundamental building blocks of life, formaldehyde (H2CO) and hydrogen cyanide(HCN), even though they were probably available, would have been concentrated sufficiently to allow further reactions to occur was likely small. And the more complex organic compounds that might have formed in this way would not have lasted long in the surface-ocean environment, because photochemical and thermal reactions would have destroyed them. Therefore, researchers have sought alternative explanations for how complex organic compounds formed.

2. The word skeptical in the paragraph 2 is closest in meaning to

(A) doubtful

(B) confident

(C) hopeful

(D) puzzled

3. According to paragraph 2, what is a problem for the explanation that life began in the oceans?

(A) Some life-forms would have been killed by high concentrations of H2CO and HCN in the early Earth’s oceans.

(B) If complex organic compounds formed in Earth’s oceans, they have been broken down by photochemical and thermal reaction.

(C) The essential elements for complex organic compounds did not exist on the early Earth.

(D) The creation of complex organic compounds on Earth's oceans was influenced by the photochemical and thermal reactions.

4. The word sufficiently in the paragraph 2 is closest in meaning to

(A) quickly

(B) repeatedly

(C) initially

(D) adequately

5. The word sought in the paragraph 2 is closest in meaning to

(A) accepted

(B) proposed

(C) challenged

(D) looked for

6. Which of the following most accurately describes the relationship of paragraph 2 to paragraph 1?

(A) Paragraph 2 accounts for the reason why some scientists doubt the theory presented in paragraph 1.

(B) Paragraph 2 give information about the way that some scientists strengthened the theory introduced in paragraph 1.

(C) Paragraph 2 exhibits another theory to the one mentioned in paragraph 1.

(D) Paragraph 2 provides information that reinforces the theory introduced in paragraph 1.

There is one possibility that the relevant organic compounds were created in space, and asteroids or comets brought them to Earth, probably as tiny dust particles. Recovered from the stratosphere (an upper region of Earth’s atmosphere), interplanetary dust particles (IDPs) is tiny particles that are known to be extraterrestrial origin. From various researches, we know that organic compounds, including amino acids, exist in IDPs as well as in some meteorite. Now, we actually have identified the fact that amino acids and many other complex organic compounds in interstellar dust clouds. It is believed that they form from reactions between charged particles and neutral molecules. Those atoms appear in interstellar dust clouds at very low temperatures-on the order of 200 or more degrees below zero on the Celsius scale. It may seem surprising that organic chemistry could occur in the interstellar environment, but it is precisely the extremely low temperatures involved that allow complex organic molecules to exist because temperatures are too cold to allow them to decompose.

。。。。此处省略余下原文、题目和答案！

2020年1月11日托福阅读真题+题目+答案：Three Theories about Origin of Life，完整版下载，10元有偿！