Submitted by admin on Mon, 04/14/2014 - 23:15
definition:
The region of the earth’s interior between the crust and the core, believed to consist of hot, dense silicate rocks (mainly peridotite)
sentence:
Hot new ocean crust forms at mid-ocean ridges, cools, and sinks back into the mantle, shedding heat and driving the plates.
difficulty:
medium
toefl frequency:
2
toefl classification: