Question

Mantle of the earth crust is ?

• A. A layer with the composition of semi-solid mineral matter
• B. A layer with the composition of fluid mineral matter
• C. A layer with the composition of semi-fluid mineral matter
• D. A layer with the composition of gaseous mineral matter

Hint:

Crust = solid, Mantle = semi-fluid, Outer core = liquid, Inner core = solid.

Answer 1

The Correct Option is C

Step 1: The Earth's structure is divided into crust, mantle, and core. 
Step 2: The mantle lies below the crust and extends up to 2,900 km deep. 
Step 3: It consists of semi-fluid silicate minerals, enabling tectonic plate movement (asthenosphere). \[ \boxed{\text{Semi-fluid mineral matter}} \]

Answer 2

Compare the physical state described in each option with the known composition of the mantle.

1. Option 1 (Semi-solid mineral matter): This description better fits the rigid lithospheric mantle just below the crust, not the mantle as a whole, which behaves more plastically at depth.
2. Option 2 (Fluid mineral matter): A fully fluid, liquid state describes the outer core, not the mantle.
3. Option 3 (Semi-fluid mineral matter): The mantle, especially the asthenosphere, is composed of semi-fluid (plastic, viscous) silicate rock that can flow slowly over geological time, driving plate tectonics.
4. Option 4 (Gaseous mineral matter): No layer of the solid Earth is gaseous; this rules out the mantle entirely.

The mantle's defining physical property is its semi-fluid, plastic behaviour beneath the rigid crust.

So, the correct answer is A layer with the composition of semi-fluid mineral matter.