Which one of the following statement is not correct about Earth's interior ?

Question

Accepted Answer

Option 3 is the correct answer because the Earth's crust is *not* mostly made of magnesium. The Earth's crust is primarily composed of oxygen, silicon, aluminum, iron, calcium, sodium, potassium, and magnesium, but oxygen and silicon are by far the most abundant elements. These elements combine to form minerals like feldspar and quartz, which are major components of the crust. While magnesium is present, it is not the *most* abundant element.

Here's why the other options are incorrect:

*   **Option 1: Asthenosphere is partially molten.** This statement is correct. The asthenosphere is a highly viscous, mechanically weak and ductile region of the upper mantle of the Earth. It lies below the lithosphere, at depths between approximately 100 and 700 km (62 and 435 miles) below the surface. It is partially molten, allowing for the movement of tectonic plates.

*   **Option 2: The core of the Earth is made of nickel and ferrous.** This statement is also correct. The Earth's core is primarily composed of iron (ferrous) and nickel.

*   **Option 4: Most part of the Earth is mantle.** This statement is also correct. The mantle makes up the largest portion of the Earth's volume, lying between the crust and the core.