* Photosynthesis: During the day, plants and algae use sunlight, water, and carbon dioxide to produce their own food (glucose) and release oxygen as a byproduct. This is called photosynthesis.
* Cellular Respiration: Both plants and algae, like all living organisms, also need to break down food to release energy for their functions. They do this through cellular respiration, where they use oxygen to break down glucose and produce energy. This process also releases carbon dioxide as a byproduct.
Therefore, plants and algae are constantly involved in a cycle of using oxygen and carbon dioxide, depending on the time of day and the processes happening within their cells. This is why they are so crucial to the balance of Earth's atmosphere.
