Internal Structure of The Earth: Which is the outermost layer of the Earth?

The crust is the Earth's outermost solid layer, comprising a thin shell of rocks and minerals that forms the Earth's surface. It varies in thickness from about 5 km under the oceans (oceanic crust) to up to 70 km under continental regions (continental crust). This layer contains all known life forms and is the foundation upon which ecosystems exist. The crust is divided into tectonic plates which drift over the underlying mantle.