Why is oxygen produced in photosynthesis and what is it used for?

By using the energy of sunlight, plants can convert carbon dioxide and water into carbohydrates and oxygen in a process called photosynthesis. As photosynthesis requires sunlight, this process only happens during the day.

primary succession occurs in essentially lifeless areas regions in which the soil is incapable of sustaining life as a result of such factors as lava flows, newly formed sand dunes, or rocks left from a retreating glacier. secondary succession occurs