I agree with Azharui. Although movie ratings do work as a general advisory and disclaimer, there may still be content that each individual parent might disagree with. For this reason, adults should monitor all movies their child sees, and should have the right to forbid their child from watching certain programs.
Oceanic crust is thinner and denser than continental crust. Oceanic crust is more mafic, continental crust is more felsic. Crust is very thin relative to Earth's radius.
