39. By saying "With Mars the scientific stakes are arguably higher than they have ever been" (Line 1, Para.4), the author means that _________________.

　　A) with Mars the risks involved are much greater than any previous space ventures

　　B) in the case of Mars, the rewards of scientific exploration can be very high

　　C) in the case of Mars, much more research funds are needed than ever before

　　D) with Mars, scientists argue, the fundamental interests of science are at issue

　　注：爭議太多，對應末段

　　40. The passage tells us that proof of life on Mars would _______________.

　　A) make clear the complex chemistry in the development of life

　　B) confirm the suggestion that bacterial fossils traveled to Earth on a meteorite

　　C) reveal the kind of conditions under which lie originates

　　D) provide an explanation why life is common in the universe

　　For centuries, explorers have risked their lives venturing into the unknown for reasons that were to varying degrees economic and nationalistic. Columbus went west to look for better trade routes to the Orient and to promote the greater glory of Spain. Lewis and Clark journeyed into the American wilderness to find out what the U.S. had acquired when it purchased Louisiana, and the Appolo astronauts rocketed to the moon in a dramatic show of technological muscle during the cold war.

　　Although their missions blended commercial and political-military imperatives, the explorers involved all accomplished some significant science simply by going where no scientists had gone before.

　　Today Mars looms(隱約出現)as humanity's next great terra incognita(未探明之地). And with doubtful prospects for a short-term financial return, with the cold war a rapidly fading memory and amid a growing emphasis on international cooperation in large space ventures, it is clear that imperatives other than profits or nationalism will have to compel human beings to leave their tracks on the planet's reddish surface. Could it be that science, which has long played a minor role in exploration, is at last destined to take a leading role? The question naturally invites a couple of others: Are there experiments that only humans could do on Mars? Could those experiments provide insights profound enough to justify the expense of sending people across interplanetary space?

　　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 meteorite(隕石)from valuable 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.