Which of the following is not true?
a) the magnetic poles have reversed periodically in earth history
b) magnetism is imparted to igneous rocks at the time of their formation
c) virtually all rock types preserve some paleomagnetic signal
d) magnetic field reversals occur about every 500,000 years
e) there have been long periods of no magnetic field
Answer: e) there have been long periods of no magnetic field
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More than ________ percent of Australia's exports now go to Asia; only ________ percent are shipped to Europe
A) 20; 25 B) 50; 1 C) 99; 1 D) 60; 11
Two dominant organisms of the rocky shore found high on the rocks of the intertidal zone are ________
A) buckshot barnacles and limpets B) goose barnacles and mussels C) keyhole limpets and Irish moss D) periwinkle snails and kelp E) sea anemones and hermit crabs
Why can an intruding mafic magma assimilate felsic country rock, but an intruding felsic magma
cannot assimilate mafic country rock? What will be an ideal response?
About 25% of of China's exports are accounted for by state-owned factories
Indicate whether the statement is true or false