The terrestrial world is green now, but it did not start out that way.
When plants first made the transition ashore more than 400 million
years ago, the land was barren and desolate, inhospitable to life.
From a plants's evolutionary view point, however, it was also a land
of opportunity, free of competitors and predators and full of carbon
dioxide and sunlight (the raw materials for photosynthesis, which
are present in far higher concentrations in air than in water). So once
natural selection had shaped the adaptations that helped plants
overcome the obstacles to terrestrial living, plants prospered and
diversified.
According to the paragraph, which of the following is true about the
terrestrial world at the time it was colonized by plants?
A. it was exposed to high levels of solar radiation.
B. it contained a limited supply of carbon dioxide.
C. it had developed 400 million years earlier.
D. it lacked the presence of any organisms
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답은 D입니다. 그런데 저는 처음에 A로 답을 골라서 틀렸거든요.
A라고 생각했던 이유는 높은 수준의 solar radiation에 노출되어 있다고 하니까
본문에 보면 free of competitors and predators and full of carbon dioxide
and sunlight라는 부분 때문에 solar radiation이 높다는 것과 sunlight가 많다는
것이 결국 같은 말인 것 아닌가 하는 생각으로 골랐거든요.. 어떤 점이 잘못된
것인지 지적해 주시면 감사할게요.