MCQ Detailed View

The Earth is made up of three main layers: the crust, the mantle, and the core. The outermost layer of the Earth is called the crust. It is the thin, solid, rocky shell that forms the Earth's surface, where all land, water, mountains, and living organisms exist.

The Earth’s crust is divided into two types:

1. 
   

   Continental Crust: Thicker (about 30–70 km), composed mainly of light rocks such as granite. It forms the continents where we live.

   
   


2. 
   

   Oceanic Crust: Thinner (about 5–10 km), made mostly of dense basaltic rocks, forming the ocean floors.

   
   

The crust is only about 1% of Earth's total volume, yet it is crucial because it supports life and holds resources like soil, minerals, water, and fossil fuels. Beneath the crust lies the mantle, a semi-solid layer of hot rock that slowly moves due to convection currents. Below that is the core, which consists of a molten outer core and a solid inner core made mainly of iron and nickel.

Key facts about the Earth's crust:

• 
  

  The average thickness of the crust is about 40 km on continents and 6 km under oceans.

  
  


• 
  

  It is broken into tectonic plates, which float on the mantle and move slowly, causing earthquakes and mountain formation.

  
  


• 
  

  The crust is primarily composed of oxygen, silicon, aluminum, iron, calcium, sodium, potassium, and magnesium.

  
  

Other options are incorrect:

• 
  

  Mantle (spelled “Mental” in option B) is the second layer, beneath the crust.

  
  


• 
  

  Core is the innermost part of the Earth.

  
  


• 
  

  “None of these” is not correct because crust is the scientific term for the Earth’s outermost layer.

  
  

The correct answer is Option A: Crust, as it is the scientifically recognized name for the thin, solid, outer layer of our planet.