Which process do plants use to release oxygen?

Plants release oxygen primarily through the process of photosynthesis, which occurs in their chloroplasts during the presence of light. In photosynthesis, plants take in carbon dioxide from the atmosphere and water from the soil. Using sunlight as an energy source, they convert these raw materials into glucose and oxygen. The glucose serves as energy and building material for the plant, while the oxygen produced is released as a by-product into the atmosphere.

This process is crucial not only for plant life but also for most living organisms on Earth, as it replenishes oxygen in the atmosphere, which is then used by animals and humans for respiration. The light-dependent reactions of photosynthesis specifically produce oxygen when water molecules are split, releasing oxygen gas as a result of that chemical reaction. Thus, the correct answer directly relates to the critical role of photosynthesis in sustaining life on Earth through oxygen production.