In more recent years，（）has been used by civilians in many new ways to determine positions，such as in automobile and boat navigation，hiking，emergency rescue，and precision agriculture and mining.

By convention，the north seeking ends of a compass’ magnets are colored（）.

A.Black
B.Blue
C.Red
D.White

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Any piece of metal on becoming magnetized will develop regions of concentrated magnetism called（）.

A.flux
B.poles
C.magnets
D.azimuth

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