us are familiar with the North Pole and South Pole in their present locations, the Earth's magnetic poles have switched several times throughout geologic history as is indicated by magnetic stripes on the ocean floor.
(the Earth's magnetic poles; have switched; T:several times; L:throughout geologic history) Context(the Earth 's magnetic poles have switched,List([79, 119))):(us; are; familiar with the North Pole and South Pole) (us; are familiar with; the North Pole)
the Earth 's magnetic poles have switched,List([79, 119))
the Earth's magnetic poles us us
have switched are are familiar with
T:several times L:throughout geologic history
familiar with the North Pole and South Pole
the North Pole