Why does oceanic lithosphere subduct, while continental lithosphere does not?
What will be an ideal response?
Oceanic lithosphere is basaltic in composition, which is rich in iron and magnesium, making it dense. Continental lithosphere is granitic in composition, rich in silica, and not very dense. In the meeting of two tectonic plates, the denser one will be the one forced to sink and subduct beneath the other. Continental crust will always be the least dense in a meeting of two plates, so it will never subduct.
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Rocks are composed of
A. glass. B. minerals. C. elements.
Electric vehicles may still be using fossil fuels
A) because they all have a supplemental gas tank. B) at a greater rate than conventional vehicles. C) because batteries require oil to operate. D) well into the 21st century. E) if their charge comes from fossil-fueled power plants.
New revisions in the food pyramid recommend
A. increasing consumption of nuts, legumes, fruits, vegetables, and whole grains. B. increasing consumption of dairy products like milk, ice cream, and cheese. C. increasing consumption of carbohydrates like rice, pasta, and potatoes. D. increasing consumption of red meat.
Which agency manages national forests?
a. U.S. Fish and Wildlife Service b. U.S. Forest Service c. Bureau of Land Management d. National Park Service