【正文】 ough direct evidence of recent eruptions is lacking, scientists believe that these volcanoes were active as recently as 100 million years ago.　B. Scientists estimate that volcanoes active more recently than 100 years ago will still have extensive impact cratering on their slopes.　C. If, as some evidence suggests, these volcanoes erupted as recently as 100 million years ago, they may continue to be intermittently active.　　D. Although these volcanoes were active as recently as 100 million years ago, there is no direct evidence of recent or ongoing eruptions.　　Q8 The word “considerably” in the passage is closest in meaning to 　　　A. Frequently　B. Significantly　　　C. Clearly　D. Surprisingly　　　　　　Q9 According to paragraph 4, what is demonstrated by the fact that craters fill in much faster on Mars than on the Moon?　A. Erosion from meteoritic impacts takes place more quickly on Mars than on the Moon.　　　B. There is more dust on Mars than on the Moon.　　　C. The surface of Mars is a dry desert.　D. Wind is a powerful eroding force on Mars.　　　Paragraph 4 　Q10 In paragraph 4, why does the author point out that Mars has few ancient craters that are less than 5 kilometers in diameter?　　　A. To explain why scientists believe that the surface matter filling Martian craters is mostly dust　B. To explain why scientists believe that the impact craters on Mars were created by meteoroids　　C. To support the claim that the Martian atmosphere is an efficient erosive agent　　D. To argue that Mars experienced fewer ancient impacts than the Moon did　　　　Paragraph 4　　　Q11 According to paragraph 5, what have scientists been able to determine from studies of large impact cratering on Mars?　　A. Some Martian volcanoes are much older than was once thought.　B. The age of Mars’s surface can vary from area to area.　　C. Large impact craters are not reliable indicators of age in areas with high volcanic activity.　D. Some areas of the Martian surface appear to be older than they actually are.　　　Paragraph 5　　　Q12 According to paragraph 6, the ejecta of Mars’s crater Yuty differs from the ejecta of the Moon’s Copernicus crater in that the ejecta of the Yuty crater　A. Has now bee part of a permafrost layer　　　B. Contains a large volume of dust, soil and boulders　　C. Suggests that liquid once came out of the surface at the crater site　　D. Was thrown a paratively long distance from the center of the crater　　　　　Paragraph 6 is marked with an arrow　Q13 Look at the four squares【■】that indicate where the following sentence could be added to the passage.　This surface feature has led to speculation about what may lie under Mars’s surface.　Where would the sentence best fit? Click on a square to add the sentence to the passage.　　　Q14 Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points.　　Drag your answer choices to the spaces where they belong. To remove an answer choice, click on it. To review the passage, click VIEW NEXT. Volcanoes and impact craters are major features of Martian geology.　　　　A. Plate motion on Mars, once considered to have played no role in shaping the planet’s surface, is now seen as being directly associated with the planet’s earliest volcanoes.　　B. Mars has shield volcanoes, some of which are extremely tall because of the planet’s low surface gravity.　　C. Although the erosive power of the Martian atmosphere ensures that Mars has fewer craters than the Moon does, impact craters are prominent on Mars’ s surface.　　D. Scientists cannot yet reliably estimate the age of the Martian surface because there has been too much erosion of it.　E. Scientists have been surprised to discover that conditions just below the surface of Mars are very similar to conditions just below the surface of the Moon　　F. Studies of crater ejecta have revealed the possibility of a layer of permafrost below the surface of Mars.　　　The Decline of Venetian Shipping　In the late thirteenth century, northern Italian cities such as Genoa, Florence, and Venice began an economic resurgence that made them into the most important economic centers of Europe. By the seventeenth century, however, other European powers had taken over, as the Italian cities lost much of their economic might.　　　This decline can be seen clearly in the changes that affected Venetian shipping and trade. First, Venic’s intermediary functions in the Adriatic Sea, where it had dominated the business of shipping for other parties, were lost to direct trading. In the fifteenth century there was little problem recruiting sailors to row the galleys (large ships propelled by oars): guilds (business associations) were required to provide rowers, and through a draft system free citizens served pulsorily when called for. █In the early sixteenth century the shortage of rowers was not serious because the demand for galleys was limited by a move to round ships (roundhulled ships with more cargo space), with required fewer rowers. █But the shortage of crews proved to be a greater and greater problem, despite continuous appeal to Venic’ s tradition of maritime greatness. █ Even though sailors’ wages doubled among the northern Italian cities from 1550 to 1590, this did not elicit an increased supply█. 　　　 The problem in shipping extended to the Arsenale, Venice’s huge and powerful shipyard. Timber ran short, and it was necessary to procure it from father and father away. In ancient Roman times, the Italian peninsula had great forest of fir preferred for warships, but scarcity was apparent as early as the early fourteenth century. Arsenale officers first brought timber fro