单项选择题

The 15 plates of the Earth are formed from ______.

A．the oceanic crusts and continental crests
B．the crusts and the mantle
C．the crusts and the top and solid part of the mantle
D．the continental crusts and the solid part of the mantle

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热门试题

单项选择题

Which of the following is the ultimate reason for the decline of tropical rain forests

A．Unfavorable climate.
B．Human abuse of forests.
C．Increase in the temperature.
D．Unusual rainfalls.

单项选择题

Seriously-deformed zones appear ______.

A．whenever the crusts move over mantle
B．when the plates move towards each other
C．in the narrow boundaries where two plates meet
D．to be the major topographical feature of the Earth