Which term denotes a mixture of gases comprising about 78% nitrogen and 21% oxygen?

Which term denotes a mixture of gases comprising about 78% nitrogen and 21% oxygen?

• A. Aero
• B. Aircraft
• C. Airport
• D. Air

Answer: (D)

The term for the gaseous mixture we breathe is air. It’s mainly nitrogen (about 78%) and oxygen (about 21%), with small amounts of other gases like argon and carbon dioxide making up the rest. These percentages are approximate and can vary a bit with altitude and humidity, but “air” is the standard name for this mixture. Other terms don’t fit as the name of the mixture: aero is a prefix meaning air and appears in specialized words, but it isn’t the noun for the gas blend. Aircraft and airport refer to a vehicle and a facility, not the gaseous mixture itself.

The term for the gaseous mixture we breathe is air. It’s mainly nitrogen (about 78%) and oxygen (about 21%), with small amounts of other gases like argon and carbon dioxide making up the rest. These percentages are approximate and can vary a bit with altitude and humidity, but “air” is the standard name for this mixture.

Other terms don’t fit as the name of the mixture: aero is a prefix meaning air and appears in specialized words, but it isn’t the noun for the gas blend. Aircraft and airport refer to a vehicle and a facility, not the gaseous mixture itself.