TPO8 第六题A选项 volcanic plains formed和volcanic activity有必然的关系吗？

neutomas

原文：[url=]

Outflow channels are probably relicsof catastrophic flooding on Mars long ago. ■They appear only in equatorialregions and generally do not form extensive interconnected networks. ■Instead,they are probably the paths taken by huge volumes of water draining from thesouthern highlands into the northern plains. ■The onrushing water arising fromthese flash floods likely also formed the odd teardrop-shaped “islands”(resembling the miniature versions seen in the wet sand ofour beaches at low tide) that have been found on the plains close to the endsof the outflow channels. ■Judging from the width and depth of the channels, theflow rates must have been truly enormous―perhaps as much as a hundred timesgreater than the 105 tons per second carried by the great Amazon river. Flooding shaped the outflow channelsapproximately 3 billion years ago, about the same times as the northern volcanicplains formed.

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题目：[url=]6. According toparagraph 2, all of the following are true of the outflow channels on MarsEXCEPT:[/url]

○They formed ataround the same time that volcanic activity was occurring on the northernplains.

○They are foundonly on certain parts of the Martian surface.

○They sometimesempty onto what appear to have once been the wet sands of tidal beaches.

○They arethought to have carried water northward from the equatorial regions.

疑问：TPO8 第六题A选项 ：volcanic plains formed和volcanic activity有必然的关系吗？我的意思是volcanic plains formed能推出A选项中的volcanic activity吗？