It isn't. Oxygen is created and used at varying rates depending on the environment. Though the amount is quite closely balanced.
Oxygen is produced by plants and blue-green algae and consumed by burning and animals breathing.
Photosynthesis by plants and phytoplankton, and respiration by living organisms help maintain the percentage of atmospheric oxygen at relatively constant levels. Photosynthesis produces oxygen as a byproduct, while respiration consumes oxygen but also releases it back into the atmosphere.
Photosynthesis by plants and algae, and respiration by animals and other organisms help maintain the percentage of atmospheric oxygen at a relatively constant level. Photosynthesis consumes carbon dioxide and produces oxygen, while respiration does the opposite.
Oxygen is produced by plants and blue-green algae and consumed by burning and animals breathing.
Photosynthesis and respiration are the two processes that help to maintain the percentage of atmospheric oxygen at relatively constant levels. Photosynthesis by plants and other organisms produces oxygen, while respiration by animals and other organisms consumes oxygen. The balance between these two processes helps keep atmospheric oxygen levels stable.
The percentage of oxygen in air remains relatively constant at about 21% up to an altitude of around 70,000 feet. Above this altitude, the percentage of oxygen starts to decrease due to the lower air pressure and density at higher altitudes.
The percentage of oxygen in sucrose is 51,41549 %.
If magnesium is heated twice but not at a constant weight, the percent of oxygen in the reaction could vary depending on the amount of magnesium present during each heating. When magnesium burns, it reacts with oxygen to form magnesium oxide, consuming oxygen in the process. If the magnesium weight decreases during the second heating, it could lead to a lower percentage of oxygen in the final product, as there would be less magnesium to react with the available oxygen. Conversely, if more magnesium is added for the second heating, the oxygen percentage would increase accordingly.
The percentage of oxygen (in mass) is 29,776 %.
The percentage of oxygen in the air remains relatively constant at around 21% regardless of location on Earth. However, the total amount of oxygen can vary due to changes in air pressure, temperature, and altitude.
The percentage of oxygen by mass in water is approximately 88.8%.
This is a colligative property which does not depend on the nature of solute is the molal boiling point elevation constant or ebullioscopic constant of the solvent.