Which statement about earth's layers is true?
-they all consist of liquid rock.
-they each vary in size and temperature.
-they are all under an equal amount of pressure.
-they will soon combine, forming a single, thick layer.

the correct answer is - they each vary in size and temperature.

the layers of the earth are not monotone, they are all different, have different sizes and properties.

the four layers are the outer crust, the mantle, the outer core, and the inner core.

the outer crust is solid. it is the top layer, the one we live on, and it is also the smallest and coldest one.

the mantle is lying right bellow the outer crust. it is much bigger, and much hotter, and it is also the layer that influences heavily the upper crust layer with its convection currents.

the outer core is liquid, very hot, relatively big, and it is the third layer (top to bottom).

the inner core is the hottest layers, it is occupying the central part of the planet, and it is the basis on top of all other layers lie on.