Theory:

We know what elements and their properties are. 
Elements are the fundamental substances that cannot be separated into simpler substances by any chemical methods. All the elements in the periodic table is an example for elements such as Oxygen, Iron, etc.
Let us now see the elements that are present in our body and the air around us.
  
Human body:
  
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Just six chemical elements make up nearly all of the mass of our bodies: Oxygen, Carbon, Hydrogen, Nitrogen, Calcium, and Phosphorus.
 
Potassium, sulphur, sodium, chlorine, and magnesium make up a large part of the least percentage point.
 
The below image represents the percentage values of elements present in the human body.
 
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Air:
 
Air is a gaseous mixture. Around \(99\) per cent of the air is made up of molecules of two different elements: nitrogen and oxygen.
 
Tiny quantities of argon and carbon dioxide make up the remainder.
 
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Trace quantities of other gases such as neon, helium, and methane are present in the air. Oxygen, a life-giving ingredient is also present in the air.