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
Get What You Need Get What You Need Get What You Need is a 2003 studio album by an Irish power pop/punk rock band The Undertones. It is the band's first collection of new studio material since their reformation with lead singer Paul McLoone, who replaced the previous singer Feargal Sharkey which occurred in November 1999. Allmusic stated in their review that "It's almost unthinkable, really, that Derry's fabled good-time teen punks of yesteryear would record and continue... let alone that their output would be anything less than embarrassing." The website also stated that "you have everything you need for a complete escape to