Pyroclastic flows are dangerous because they ____
a. ?contain poisonous sulfur compounds
b. ?cause magma chamber collapse
c. ?move very fast, and extend a long distance
d. ?move very fast over a short distance
e. ?move at unpredictable speeds
ANSWER: c
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Moldova, after it became an autonomous republic sought ethnic reunification with
A) Bulgaria. B) Hungary. C) Austria. D) Romania. E) Slovenia.
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Igneous rocks that are silica-rich with high aluminum, sodium, and potassium are ________ rocks.
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