Why do the amount of certain gases in the atmosphere change from time to time?

The amounts of certain gases in the atmosphere fluctuate due to a variety of natural and human-induced factors. Natural processes, such as volcanic eruptions, oceanic activity, and photosynthesis, can release or absorb gases like carbon dioxide and oxygen. Additionally, human activities, including fossil fuel combustion, deforestation, and industrial emissions, significantly contribute to changes in atmospheric gas concentrations. Seasonal variations and climate change also play a role, influencing the uptake and release of gases in the environment.