[单项选择]

The discovery of life beyond Earth would transform not only our science but also our religions, our belief systems and our entire world-view. For in a sense, the search for extraterrestrial life is really a search for ourselves--who we are and what our place is in the grand sweep of the cosmos.
Contrary to popular belief, speculation that we are not alone in the universe is as old as philosophy itself. The essential steps in the reasoning were based on the atomic theory of the ancient Greek philosopher Democritus. Yet philosophy is one thing, filling in the physical details is another. Although astronomers increasingly suspect that biofriendly planets may be abundant in the universe, the chemical steps leading to life remain largely mysterious.
Traditionally, biologists believed that life is a freak--the result of a zillion-to-one accidental concatenation of molecules. It follows that the likelihood of its happening again elsewhere in the cosmos is infinitesimal.
A. justifying popular beliefs.
B. making comparisons.
C. looking back on history.
D. posing sharp contrasts.

[单项选择]The discovery of life beyond Earth would transform not only our science but also our religions, our belief systems and our entire world-view. For in a sense, the search for extraterrestrial life is really a search for ourselves--who we are and what our place is in the grand sweep of the cosmos.
Contrary to popular belief, speculation that we are not alone in the universe is as old as philosophy itself. The essential steps in the reasoning were based on the atomic theory of the ancient Greek philosopher Democritus. Yet philosophy is one thing, filling in the physical details is another. Although astronomers increasingly suspect that biofriendly planets may be abundant in the universe, the chemical steps leading to life remain largely mysterious.
Traditionally, biologists believed that life is a freak--the result of a zillion-to-one accidental concatenation of molecules. It follows that the likelihood of its happening again elsewhere in the cosmos is infinitesimal. This viewpoi
A. justifying popular beliefs.
B. making comparisons.
C. looking back on history.
D. posing sharp contrasts.