English: In the sunlight of daytime, the natural reaction of photosynthesis occurs in the plants. The energy from the sun transforms the water and carbon dioxide to the food, sugar or glucose and oxygen. In the night time, the oxygen is converted to carbon dioxide with the plant respiration process. Additionally, just about all of the oxygen in the atmosphere is produced by photosynthetic organisms. Evidence in the geological record has long suggested that the first photosynthetic organisms oxygenated the atmosphere and paved the way for more complicated, oxygen-requiring organisms early in the history of life on Earth. According to an April 11, 2009 article in “Science News,” photosynthetic organisms may have begun to oxygenate the atmosphere as long as 3.46 billion years ago. References: 1) http://www.nhptv.org/natureworks/nwepphotosynthesis.htm; 2) https://sciencing.com/type-energy-produced-photosynthesis-5558184.html