1. Crust:

* Composition: Primarily composed of igneous, sedimentary, and metamorphic rocks. The most abundant elements are oxygen, silicon, aluminum, iron, calcium, sodium, potassium, and magnesium.

* Types:

* Oceanic Crust: Thinner (5-10 km), denser, and younger than continental crust. Made up mostly of basalt and gabbro.

* Continental Crust: Thicker (30-70 km), less dense, and older than oceanic crust. Composed of a variety of rocks, including granite, gneiss, and schist.

2. Mantle:

* Composition: Mostly solid rock, but behaves like a very viscous fluid over long periods due to intense heat and pressure. Dominated by silicate minerals, primarily olivine and pyroxene.

* Sub-Layers:

* Upper Mantle: Extends from the base of the crust to about 660 kilometers. Contains the asthenosphere, a partially molten zone that allows tectonic plates to move.

* Lower Mantle: Extends from 660 kilometers to 2,890 kilometers. More rigid than the upper mantle.

3. Outer Core:

* Composition: Liquid iron and nickel, with traces of other elements like sulfur, silicon, and oxygen.

* Characteristics: Generates Earth's magnetic field through convection currents.

4. Inner Core:

* Composition: Solid iron and nickel, with a trace of other elements.

* Characteristics: Despite intense heat, pressure is so immense that the iron and nickel remain solid.

Note: The exact composition of Earth's layers varies slightly throughout, and scientists are still studying the details.