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 You Need (The Twilight Zone) What You Need (The Twilight Zone) "What You Need" is episode 12 of the American television anthology series "The Twilight Zone". It is based on the short story of the same name by Lewis Padgett (Henry Kuttner and C. L. Moore). Pedott , a peddler, has the curious ability to give people exactly what they need before they need it. He enters a coffee shop where he first gives a woman a vial of cleaner. Then he gives a down-on-his-luck ex-baseball player a bus ticket to Scranton, Pennsylvania. Moments later, the ball player receives a phone call at the cafe