MCQ Detailed View

The atmosphere is the blanket of air that surrounds the Earth. It is made up of gases such as nitrogen, oxygen, carbon dioxide, and small amounts of other gases. As we move higher above the Earth’s surface, the atmosphere changes. One of the most important changes is that the air becomes thinner.

“Thinner” air means that the number of air molecules, or the air density, decreases as altitude increases. At sea level, the air is packed tightly because of the weight of the atmosphere pressing down from above. This creates high air pressure and more oxygen molecules in every breath.

When we go higher, such as climbing a mountain or flying in an airplane, there is less air above us pressing downward. This reduces air pressure and makes the air less dense. As a result, the oxygen available also decreases. This is why people often experience shortness of breath or need oxygen support at high altitudes.

Another effect of thinner air is lower temperatures. In the troposphere, which is the lowest layer of the atmosphere, temperature usually decreases with height. That is why mountaintops are much colder than areas at sea level.

This concept is important in everyday life. For example:

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  Pilots must understand how thinner air affects airplane lift.

  
  


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  Athletes training at high altitudes adapt to lower oxygen levels.

  
  


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  Weather science depends on studying air pressure and density at different heights.

  
  

So, the correct answer is Thinner. As we go higher into the atmosphere, the air pressure and density decrease, making the air thinner.