Explanations:The composition of the Earth's atmosphere is primarily made up of nitrogen (about 78%) and oxygen (about 21%). Other gases such as argon, carbon dioxide, and trace amounts of other gases make up the remaining 1%. At sea level, the air pressure is higher, and the atmosphere is denser, meaning that there are more molecules of air per unit volume. As altitude increases, the air pressure decreases, and the atmosphere becomes less dense. This means that the number of molecules of air per unit volume also decreases.
While the relative proportions of nitrogen and oxygen in the atmosphere remain relatively constant, the absolute number of molecules of each gas per unit volume decreases with altitude. This is why the concentration of oxygen in the air decreases at high altitudes. The decrease in oxygen concentration can have significant physiological effects on humans and other organisms that are not adapted to high altitudes, leading to conditions such as altitude sickness.
It is important to note that while the concentration of oxygen decreases, the concentration of nitrogen also decreases, but not as significantly as oxygen. This is because nitrogen makes up a larger proportion of the atmosphere. Other gases such as argon and carbon dioxide also decrease in concentration, but their effects are less noticeable due to their lower concentrations in the atmosphere.
Understanding the changes in atmospheric composition with altitude is crucial for various fields, including meteorology, aviation, and mountaineering. It is also relevant for understanding the physiological effects of high altitude on the human body and the adaptations required to survive in such environments.