The oxygen cycle is the process by which oxygen is exchanged between the atmosphere, living organisms, and the environment. Plants, through photosynthesis, absorb carbon dioxide and release oxygen, which is essential for the survival of most living beings. Animals and humans then inhale this oxygen to breathe and release carbon dioxide back into the atmosphere. In addition to photosynthesis, oxygen is also produced by aquatic plants and phytoplankton in oceans and lakes. Decomposers break down organic matter, returning nutrients to the soil and releasing oxygen in the process. This continuous cycle maintains the balance of oxygen in our atmosphere, supporting life on Earth.