Read the following passage and then choose the best answer for each question.

The atmosphere of Venus is quite different from ours. Measurements taken from the Earth show a high concentration of carbon dioxide in the atmosphere of Venus. In fact, carbon dioxide makes up 96 percent of Venus atmosphere; nitrogen makes up almost all the rest. The Earth’s atmosphere, by comparison, is mainly nitrogen, with a fair amount of oxygen as well. Carbon dioxide makes up less than 0.1 percent of the terrestrial atmosphere.
The surface pressure of Venus* atmosphere is 90 limes higher than the pressure of Earth’s atmosphere, as a result of the large amount of carbon dioxide in the former. Throughout Earth’s history, carbon dioxide on Earth has mixed with rain to dissolve rocks; the dissolved rock and carbon dioxide eventually flow into the oceans, where they precipitate to form new terrestrial rocks, often with the help of life-forms. If this carbon
dioxide were released from the Earth’s rocks, along with owercarton dioxide trapped in seawater, our atmosphere would become as dense and have as high a pressure as that of Venus. Venus, slightly closer to the Sun than Earth and thus hotter, had no’oceans in which the carbon dioxide could dissolve or life to help take up the carbon.
Also, Venus has probably lost almost all the water it ever had. Since Venus is closer to the Sun than the Earth is, its lower atmosphere was hotter even early on. The result was that more water vapor went into its upper atmosphere, where solar ultraviolet rays broke in up into hydrogen and oxygen. The hydrogen, a light gas, escaped easily; the oxygen has combined with other gasses or with iron on Venus surface.
Studies from the Earth show that the clouds on Venus are primarily composed of droplets of sulfuric acid, with water droplets mixed in Sulfuric acid may sound strange as a cloud constituent, but the Earth too has a significant layer of sulfuric acid droplets in its stratosphere. However, the water in the lower layers of the Earth’s atmosphere, circulating because of weather, washes the sulfur compounds out of these layers, whereas Venus has sulfur compounds in me lower layers of its atmosphere in addition to those in its clouds.

1. What does the passage mainly discuss?

2. The phrase “the former” in line7 refers to

3. The word “eventually” in line 8 is closest in meaning to

4. According to the passage, what causes Venus’ high surface pressure?

5. Why does the author begin the sentence in lines 9-10 with the phrase “If this carbon dioxide were released from Earth’s rocks,.-.”‘

6. The word “trapped” in line 10 is closest in meaning to

7. According to the passage, which of the following has resulted from processes involving Earth’s carbon
dioxide?

8. The passage suggests that which of the following helps explain; why Earth has kept most of its water?

9. According to the passage, what happened to oxygen on Venus’?

10. The word “constituent” in line 19 is closest in meaning to