Running Water on Mars TOEFL Reading

Remains

 Sites

Requirements

 Sources

To emphasize the great size of the volume of water that seems to flow through Mars's outflow channels

To indicate dare to used by scientists to estimate how long ago Mars’ outflow channels were formed 

To argue that flash floods on Mars may have been powerful enough to cause tear-shaped Islands to form 

To argue that the force of flood waters on Mars was powerful enough to shape the northern volcanic plains

They formed at around the same time that volcanic activity was occurring on the Northern plains

 They are found only on certain parts of the Martian surface

They are sometimes empty on to what appear to have once been the wet Sands of tidal beaches

They are thought to have carried water Northwood from the equatorial regions 

What are some regions of Mars that may have once been covered with an ocean?

 Where do Mission scientists believe that the river forming the delta emptied?

Approximately how many craters on Mars do Mission scientists believe me once have been lakes filled with water?

 During what period of Mars is history do some scientists think it may have had large bodies of water?

  the polar regions of Mars were once more extensive than they are now

 a large part of the northern lowlands may have once been underwater

 Deltas were once a common feature of the Martian  landscape

 the shape of the Hellis Basin in has changed considerably over time 

Lakes on early Mars were likely as large as some oceans on Earth's surface today

If there is any liquid  water at all on Mars's surface today, it's quantity is much smaller than the amount that likely existed in the past 

Small scale goal is on Mars provide convincing evidence that liquid water existed on Mars in the recent past 

The small amount of water vapor in the Martian atmosphere suggest that there has never been liquid water on Mars 

ancient oceans of Mars contained only small amounts of carbon

 the climate of Mars may not have been suitable for the formation of large bodies of water

the climate of Mars may not have been suitable for the formation of large bodies of water

Liquid water may have existed on some parts of Mars's surface for long periods of time

 the ancient oceans that were formed on Mars dried up during periods of cold dry weather 

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