The correct answer is D. Volcano.
The crust, mantle, and core are all layers of the Earth. The crust is the outermost layer, the mantle is the middle layer, and the core is the innermost layer. The crust is made of solid rock, the mantle is made of solid and liquid rock, and the core is made of solid iron and nickel.
A volcano is a mountain that is formed when magma, or molten rock, erupts from the Earth’s surface. Volcanoes can be found on all of the Earth’s continents, as well as on the ocean floor.
The crust, mantle, and core are all essential parts of the Earth. The crust provides a solid surface for us to live on, the mantle helps to regulate the Earth’s temperature, and the core generates the Earth’s magnetic field. Volcanoes, on the other hand, are not essential to the Earth’s existence. They can be destructive, but they can also be beneficial, as they can create new land and provide resources such as lava and ash.