Oxygen makes up about 20% of the atmosphere and is the second most abundant element in the air. Nitrogen is the most abundant component at roughly 78%. Water (H2O) makes up roughly 2 - 4%. The rest are trace gases of less than 1%.
The amount of inhaled air compared to the quantity of air exhaled by an average human is shown in the graph below. This illistration was copied from Dr. Jay Wile's "Exploring Creation With Physical Science" book. Page 35/ Figure 2.5. One would think that one should inhale the oxygen and exhale CO2 and those are the only substances involved, but that is not the case. One would also wonder why God did not make it so that the quantity of oxygen contained in the air 100% (or at least 85%), but that also is not the case, why? Well, first of all, notice that we inhale a lot of oxygen, as well as exhale a lot of oxygen, because normally we do not need al of oxygen we inhale, so we exhale the excess oxygen. Second of all, if the air contained too much oxygen, it would be way too violent on the lung tissue.
In the process of respiration OXYGEN is taken in from the atmoshpere and CO2 is released.
Exhaled air contains 16% oxygen and 21% when inhaled.
Octopuses breathe air through gills, which extract oxygen from water. They can also absorb oxygen directly from the air through their skin.
To increase oxygen levels in a room, you can add more plants as they release oxygen during photosynthesis. Opening windows and using air purifiers can also help improve air circulation and oxygen levels.
Air is approximately 20% Oxygen.
Oxygen - yes. Air - no. Not much of that around underwater.
The Earth's atmosphere is composed of roughly 21% oxygen. This level of oxygen in the air is ideal for human respiratory needs.
About 20% of the volume of the air in the room is oxygen.
Around 16% of the air you breathe out is oxygen. This percentage decreases from the 21% of oxygen in the air you inhale due to the exchange of gases that occurs during respiration.
A small percent . exhaled air always contains oxygen .
Concentration of oxygen in dry air is 20,946 %.
ideally 21% (20.95%)
Oxygen, of course.
The concentration of oxygen in the air is much much higher than in the water. This make obtaining oxygen much easier and strenuous activity (to a level higher than that is water) possible.
Oxygen keeps animals alive, Nitrogen is not much use.
In 1973, the composition of Earth's atmosphere was roughly the same as it is today, with oxygen making up about 21% of the air.