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It is clear from the passage that Antarctic flying .............. .
The worst condition of Antarctic flying is called the "white
out." Pilots have said it is like "flying in a bowl of milk."
Atmospheric conditions make the snow and sky appear
to blend together. There is no horizon, which leaves
them without any visible check point above or below the
airplane. Despite these handicaps, aviation is vital to
polar exploration. Airplane flights, however, cannot be
used for getting many kinds of information. Plant and
animal life cannot be studied from the air. An air
observer cannot make detailed examinations of mineral
deposits, and he cannot obtain records of weather
conditions in stormy times when airplanes cannot be
flown. For all such studies, men must still work on the
ground.