What is the outermost layer of the Earth?

• A. The mantle
• B. The crust
• C. The core
• D. The inner core

Answer: (B)

Earth is built in layers, like an onion. The layer you would first encounter at the surface is the crust, the outermost layer of the planet. The crust forms the land we live on and the ocean floors, and it’s thinner than the layers beneath. There are two types: continental crust, which is thicker and lighter rock, and oceanic crust, which is thinner and more dense basalt. Beneath the crust lies the mantle, and toward the center are the core, which has a liquid outer part and a solid inner part. Because the crust sits on top of the mantle and all the way above the core, it is the outermost layer.