Question

What is the crust?

1) The outer layer of the earth
2) The layer that is hard and brittle
3) Made mostly of basalt and granite
4) All of the above

Answer 1

The crust is the thin, outermost layer of Earth, made mostly of basalt in the oceanic crust and granite in the continental crust, and is both hard and brittle.

Step-by-step explanation:

The crust is the outermost layer of Earth's structure and is categorized into two types: oceanic and continental. The oceanic crust is predominantly made up of basalt and is thinner, covering 55% of Earth's surface, mostly under oceans. Contrastingly, the continental crust is thicker, consisting mainly of granite, and spans across 45% of the surface. Both crust types are comprised of igneous rock, formed from the cooling of molten materials. The crust is a cold, thin, brittle shell with varying thickness, but it only accounts for about 0.3% of Earth's total mass. Its composition primarily includes silicon, oxygen, iron, aluminum, and magnesium, with densities around 3 g/cm³.