Question

Which of these best describes Earth’s crust?

Inner layer consisting of two parts
Middle layer, density increases with depth
Top portion called asthenosphere, thickest layer
Thinnest under the oceans and thickest under continents

Answer 1

D. Thinnest under the oceans and thickest under continents

Answer 2

D. Thinnest under the oceans and thickest under continents

Explanation - Earth is divided into three layers - crust, mantle and core. Crust is the outer most layer, mantle being the middle one and core is the innermost layer.

Beneath the oceans, crust is thin whereas beneath the continents, crust is the thickest. The density of the Earth's crust is least or minimum as compared to the mantle and core. The composition of crust are as follows -

1. Solid rock has silicon and oxygen .
2. Oceanic crust has basalt .
3. Continental crust has granite .