Answer: -
b. Oceanic crust is denser than continental crust, causing oceanic crust to sink down below continental crust.
Explanation:-
Oceanic crust is denser than the continental crust as it has iron, basalt, magnesium. On the other hand continental crust consists of granite and aluminium. The rocks that have oceanic crust are thus denser than the rocks that have continental crust. Continental crust is considerable thicker.
Due to the difference in the density when oceanic crust and continental crust meet at the subduction zones, the oceanic crust is sub ducted back into the mantle. Continental crust is the oldest part and underlies beneath the continent.
A layer of sedimentary and metamorphic rocks too form on the tops of the continental crust.On the basis of the above explanation, Oceanic crust is denser than continental crust, causing oceanic crust to sink down below continental crust is the correct option.
