题目选项分析

The features of the floor of the Kasei Valles on Mars look just like those at the base of Antarctic ice streams, suggesting that flowing ice may have carved the giant Martian channels previously attributed to cataclysmic floods.

The features of the floor of the Kasei Valles on Mars look just like those at the base of Antarctic ice streams, a suggestion that flowing ice may have carved the giant Martian channels previously attributed to cataclysmic floods.