MCQ Detailed View

Earth is often referred to as the “Blue Planet” because of its vast water coverage. Approximately 71% of the Earth’s surface is covered by water, making it the dominant feature of our planet’s outer layer. This water is distributed across oceans, seas, lakes, rivers, glaciers, and groundwater sources, forming the hydrosphere.

Breakdown of Earth's Water Distribution:

1. 
   

   Oceans and Seas:

   
   
   
   
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     Make up about 97% of all water on Earth.

     
     
   
   
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     Saltwater is not directly drinkable but plays a vital role in regulating climate and supporting marine ecosystems.

     
     
   
   
   
   


2. 
   

   Freshwater:

   
   
   
   
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     Accounts for only about 3% of all water, mostly stored in glaciers, ice caps, groundwater, rivers, and lakes.

     
     
   
   
   
   


3. 
   

   Atmospheric Water:

   
   
   
   
   • 
     

     A small amount exists in the form of water vapor, clouds, and precipitation.

     
     
   
   
   
   

Significance of Water Coverage:

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  Climate Regulation: Oceans absorb solar heat and help distribute it globally through ocean currents, stabilizing temperatures.

  
  


• 
  

  Life Support: All known life forms depend on water for biological processes like hydration, nutrient transport, and metabolic reactions.

  
  


• 
  

  Geological Shaping: Water contributes to erosion, weathering, and the formation of landscapes.

  
  

Why Other Options Are Incorrect:

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  61% or 67%: These percentages underestimate the actual water coverage.

  
  


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  76%: Slightly overestimates, as landmasses occupy around 29% of Earth's surface.

  
  

With 71% of the planet's surface covered by water, Earth appears mostly blue when viewed from space. However, only a small fraction is accessible freshwater, making water conservation critical for life.Thus, the correct answer is Option C: 71%, the scientifically accepted figure for Earth’s water-covered  surface.