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 U Need? What U Need? "what U need?" is a single recorded by Chinese singer Lay for his debut extended play "Lose Control" . It was pre-released on October 7, 2016 by S.M. Entertainment as a birthday gift for Lay's fans. Produced by Devine Channel and Lay, "what U need?" is described as a "Pop-R&B" song with lyrics about being overwhelmed by a loved one. "what U need?" music video was released on October 7, 2016. It features Lay with backup dancers dancing the song's choreography. Lay performed "what U need?" for the first time on October 9 at the 2016 Asia