What essential gas, produced mostly by oceans and rainforests, is necessary for many organisms to breathe?

Oxygen is crucial for the survival of many organisms because it is a key component of cellular respiration, the process by which cells convert glucose and oxygen into energy, carbon dioxide, and water. Most complex life forms, including humans, rely on oxygen to produce the energy needed for various bodily functions.

Oceans and rainforests are significant contributors to the Earth's oxygen supply through the process of photosynthesis. During photosynthesis, plants, algae, and some bacteria use sunlight to convert carbon dioxide and water into glucose and oxygen. This oxygen is then released into the atmosphere, making it available for organisms to breathe.

Understanding the vital role of oxygen emphasizes the importance of preserving these ecosystems, as their health directly affects the abundance of oxygen available in the environment.