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对于底物浓度与反应速率关系的叙述，恰当的是
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磺胺类药物抑菌作用的机制是
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 Louisianan, and the Apollo 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 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 experiment that only human could do on Mars Could those experiments provide insights profound enough to justify the expense of sending people across interplanetary spaceWith 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 (陨石) 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. According to the passage, the chief purpose of explorers in going to unknown places in the past was ______.
对于变构酶变构调节的叙述，恰当的是
pH与酶促反应速度关系的叙述，恰当的是
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