What percentage of the air is oxygen?

The correct percentage of oxygen in the air is approximately 21%. This measurement refers to the composition of Earth's atmosphere, which is made up of various gases. Oxygen, while essential for life, is only a small portion of the total atmosphere compared to nitrogen, which constitutes about 78%. The remaining composition includes other gases, such as argon, carbon dioxide, and trace elements.

Understanding the significance of these percentages is important in fields like agriculture, where oxygen plays a crucial role in plant respiration and overall ecosystem health. Recognizing that oxygen levels are relatively low compared to nitrogen can also impact practices related to air quality management and plant growth strategies. This fundamental knowledge of atmospheric composition lays the groundwork for more advanced studies in environmental science and agricultural practices.