What is Layer 4?

Question

A.
It is the solid, dense crust.


B.
It is the solid, brittle upper mantle.


C.
It is the liquid, quickly rotating inner core.


D.
It is the semiliquid, slow moving outer core.

Answer 1

The term "Layer 4" is not a standard designation for layers of the Earth, but based on your options, the most fitting answer related to Earth's internal structure would be:

D. It is the semiliquid, slow moving outer core.

In geology, the Earth's layers typically include the crust, mantle (upper and lower), outer core (which is liquid), and inner core (which is solid). The outer core is indeed a semiliquid layer that contributes to Earth's magnetic field through its fluid motion.