MCQ Detailed View

The ozone layer is a thin, naturally occurring layer of gas located in the stratosphere, about 15 to 35 kilometers above Earth’s surface. It is made up of ozone molecules (O₃), which are a special form of oxygen consisting of three oxygen atoms. One of its main functions is to filter harmful ultraviolet (UV) rays from the Sun, protecting all living organisms on Earth from radiation damage.The Sun emits different types of UV rays: UV-A, UV-B, and UV-C. Without the ozone layer, most of these high-energy rays would reach the Earth's surface, causing severe problems such as:

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  Increased risk of skin cancer in humans due to DNA damage from UV rays.

  
  


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  Eye problems like cataracts from prolonged exposure.

  
  


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  Reduced crop yield as UV radiation harms plant tissues.

  
  


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  Damage to aquatic life, especially plankton that forms the base of the food chain.

  
  

Other options in the question are not correct:

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  Preventing global warming: The ozone layer does not control Earth’s temperature. Global warming is mainly caused by greenhouse gases like carbon dioxide and methane.

  
  


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  Absorbing pollution: The ozone layer does not clean pollutants; in fact, human-made pollutants like CFCs (chlorofluorocarbons) damage the ozone layer.

  
  


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  All of the above: Only the UV-filtering function is correct, making this option inaccurate.

  
  

When the ozone layer is depleted, more harmful UV radiation reaches Earth, leading to health and environmental issues. International agreements, like the Montreal Protocol, were created to reduce ozone-depleting chemicals, allowing the layer to recover gradually.

In short, the main protective function of the ozone layer is to absorb and filter out harmful ultraviolet rays, making Option 2 the correct answer.