Which of the following statements best describes the formation of secondary magmas?
A) Decompression melting creates a mafic magma from mantle material.
B) Iron-rich minerals will form in a cooling magma and leave the remaining melt with a more silicic composition.
C) Partial melting of felsic rocks creates a silica-rich magma.
D) Water dehydrating from a subducted plate will melt mantle material.
Answer: B
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The Caspian Sea
A) is in much greater danger than is the Aral Sea. B) is threatened by oil-industry pollution. C) has increased in size over the last three decades. D) is the smallest lake in Central Asia. E) drains into the Mediterranean.
Evaluate the costs and benefits (more than economic) of using coal, oil, and natural gas. In your evaluation, provide the pros and cons and the context in which each energy source would work best.
What will be an ideal response?
Global winds between 40 and 60 degrees South latitude blow Westerly. What direction do surface currents move in this region?
A) northerly B) easterly C) westerly D) They move in a clockwise circular pattern.
Whirlpool-like storms are called all of the following EXCEPT?
a. cyclones b. hurricanes c. monsoons d. typhoons e. willy-willies