With Mars the scientific stakes are arguably higher than they have ever been. The issue of whether life ever existed on the planet, and whether it persists to this day, has been highlighted by mounting evidence that the Red Planet once had abundant stable, liquid water and by the continuing controversy over suggestions that bacterial fossils rode to Earth on a mctcorite from Mars. A more conclusive answer about life on Mars, past or present, would give researchers invaluable data about the range of conditions under which a planet can generate the complex chemistry that leads to life. If it could be established that life arose independently on Mars and Earth, the finding would provide the first concrete clues in one of the deepest mysteries in all of science: the prevalence of life in the universe.

　　36.According to the passage, the chief purpose of explorers in going to unknown places in the past was .

　　A) to display their countrys military might C) to find new areas for colonization

　　B) to accomplish some significant science D) to pursue commercial and state interests

　　37.At present, a probable inducement for countries to initiate large-scale space ventures is .

　　A) international cooperation C) scientific research

　　B) nationalistic reasons D) long-term profits

　　38. What is the main goal of sending human missions to Mars?

【六级考试阅读理解真题精选练习（20）】相关文章：

★ 2009年12月英语六级阅读理解的全真模拟题九

★ 英语四级考试阅读习题及答案解析(8)

★ 2014年12月大学英语六级阅读真题训练

★ 六级阅读理解练习 2011.04.14

★ 2013年大学英语六级考试阅读的训练题4

★ 2010年大学英语六级考试阅读的技巧

★ 2013年6月英语六级考试备考深度阅读试题模拟与解析（10）

★ 英语六级考试冲刺的练习阅读篇49

★ 2011年最新六级阅读理解练习（22）

★ 2011年最新六级阅读理解练习（5）