Photosynthesis More recent studies, reported in March 2018, also suggest that photosynthesis may have begun about 3.4 billion years ago. The main source of oxygen in the Earth's atmosphere derives from oxygenic photosynthesis, and its first appearance is sometimes referred to as the oxygen catastrophe. Geological evidence suggests that oxygenic photosynthesis, such as that in cyanobacteria, became important during the Paleoproterozoic era around 2 billion years ago. Modern photosynthesis in plants and most photosynthetic prokaryotes is oxygenic. Oxygenic photosynthesis uses water as an electron donor, which is oxidized to molecular oxygen () in the photosynthetic reaction center. Several groups of animals
What I Need What I Need "What I Need" is a song by American recording artist Ray J. It was written by Rodney "Darkchild" Jerkins, LaShawn Daniels, Fred Jerkins III, and Ray J for his 2005 album "Raydiation", while production was handled by the former. Released as the second single from the album following "One Wish", it reached number 58 on "Billboard"s Hot R&B/Hip-Hop Songs chart. "What I Need" earned generally positive reviews by critics. "Billboard" magazine felt that the song "should be enough to momentum. Here, Ray J's vocals once again seem strained as he cops another plea to the woman he