'Runnin Water on Mars' IELTS/TOEFL Reading

The word “merge” in the passage is closest in meaning to ...

• expand

• separate

• straighten out

• combine

What does the discussion in paragraph 1 of runoff channels in the southern highlands suggest about Mars?

• The atmosphere of Mars was once thinner than it is today.

• The river systems of Mars were once more extensive than Earth’s.

• Large amounts of rain once fell on parts of Mars

• The rivers of Mars began to dry up about 4 billion years ago.

The word “relics” in the passage is closest in meaning to

• remains

• sites

• requirements

• sources

According to paragraph 2, all of the following are true of the outflow channels on Mars except:

• To emphasize the great size of the volume of water that seems to have flowed through Mars’ outflow channels

• To indicate data 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

The word “miniature” in the passage is closest in meaning to

• temporary

• small

• multiple

• familiar

According to paragraph 2, all of the following are true of the outflow channels on Mars except:

• 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 sometimes empty onto what appear to have once been the wet sands of tidal beaches

• They are thought to have carried water northward from the equatorial regions

All of the following questions about geological features on Mars are answered in paragraph 3 except:

• 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 may once have been lakes filled with water?

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

According to paragraph 3, images of Mars’ surface have been interpreted as support for the idea that

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

• a large part of the northern lowlands may once have been under water

• deltas were once a common feature of the Martian landscape

• the shape of the Hellas Basin has changed considerably over time

What can be inferred from paragraph 3 about liquid water on Mars?

• If ancient oceans ever existed on Mars’ surface, it is likely that the water in them has evaporated by now

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

• Small-scale gullies 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 suggests that there has never been liquid water on Mars

According to paragraph 4, what do the 2003 global Surveyor data suggest about Mars?

• Ancient oceans on Mars contained only small amounts of carbon

• 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’ surface for long periods of time

• The ancient oceans that formed on Mars dried up during periods of cold, dry weather