What are the subdivision of the earth's top-most skim

Earth's top most skin is called Crust. There are two sub divisions of earth's top most skin namely Oceanic crust and Continental crust.

Explanation:

Top most skin of the earth is called Crust. It is that layer where we live. It consist of oceans and continents. Continental crust consist of landmasses. The oceanic crust consist of oceans at a depth of 5 to 10 KM. This crust is thinner. The continental crust is thick.

Oceanic crust consist of iron, magnesium, silicate etc. Continental crust consist of sodium, potassium, silicate rocks.

Continental crust consist of sedimentary and metamorphic rocks which form the continents. Continental crust is 30 to 50 km thick. It allow the existence of land life. Oceanic crust is more dense than continental crust. It is due to this reason that the elevation of continents is higher than oceans.

Continental crust is older than oceanic crust. Oceanic crust subject to recycling but continental crust is not recycled. So due to this fact oceanic crust remain young. The temperature of both continental crust and oceanic crust increases with the depth.