Which of Earth’s layers is the thinnest? A. outer core B. crust C. mantle D. inner core
The Correct Answer and Explanation is:
Correct Answer: B. crust
The Earth’s crust is the thinnest of all its layers. It makes up less than 1 percent of Earth’s total volume and lies on the surface where we live. The crust can be divided into two types: continental crust, which forms the continents, and oceanic crust, which lies beneath the ocean floors. Continental crust is generally thicker, averaging around 35 kilometers, while oceanic crust is thinner, averaging about 7 to 10 kilometers.
In comparison, the mantle extends to a depth of about 2,900 kilometers and constitutes approximately 84 percent of Earth’s volume. Beneath the mantle lies the outer core, which is a liquid layer composed mainly of iron and nickel. It spans from about 2,900 kilometers to 5,150 kilometers below the surface. Finally, the inner core is solid and extends from 5,150 kilometers to the center of the Earth at about 6,371 kilometers deep.
Despite being the thinnest, the crust plays a crucial role in Earth’s geology and supports all life forms. It contains all known landforms, oceans, and ecosystems. The crust also holds important resources such as minerals, fossil fuels, and groundwater.
Tectonic plates, which are segments of the Earth’s crust and uppermost mantle, float on the semi-fluid portion of the mantle known as the asthenosphere. Their movement causes earthquakes, volcanic activity, and the formation of mountains. These dynamic interactions highlight the importance of the crust in shaping Earth’s surface.
In summary, while the crust is the outermost and thinnest layer of the Earth, it is vital to life and geological processes. Its unique characteristics set it apart from the much thicker mantle and the deeper core layers, making it essential for both scientific understanding and human survival.
