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 Can Do for You What I Can Do for You "What I Can Do for You" is a single by Sheryl Crow from the album "Tuesday Night Music Club" released on A&M Records. It was originally released in 1993 and the single includes a rare speedier version of LP track "The Na-Na Song" (i.e. "Volvo Cowgirl 99"). "What I Can Do for You" managed only number 97 when first released at the end of 1993, but was re-released after the success of "All I Wanna Do" and "Strong Enough". Two CD singles were released, with the second one being a limited edition including a