gre考试阅读真题解析(B)_GRE阅读

gre考试阅读真题解析(B)

　　Since 1953, many experimental attempts to synthesize the chemical constituents of life under primitive Earth conditions have been performed, but none of these experiments has produced anything approaching the complexity of the simplest organism. They have demonstrated, however, that a variety of the complex molecules currently making up living organisms could have been present in the early ocean and atmosphere, with only one limitation: such molecules are synthesized far less readily when oxygen-containing compounds dominate the atmosphere. Therefore some scientists postulate that the Earths earliest atmosphere, unlike that of today, was dominated by hydrogen, methane, and ammonia.

　　From these studies, scientists have concluded that the surface of the primitive Earth was covered with oceans containing the molecules fundamental to life. Although, at present, scientists cannot explain how these relatively small molecules combined to produce larger, more complex molecules, some scientists have precipitously ventured hypotheses that attempt to explain the development, from lager molecules, of the earliest self-duplicating organisms.

　　24. According to the passage, which of the following can be inferred about the process by which the chemical constituents of life were synthesized under primitive Earth conditions?